Use After Free
Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.
How It Works
Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated. When memory is freed, it returns to the allocator's pool and may be reallocated for an entirely different purpose. The original pointer becomes "dangling"—it still points to that memory location, but the contents are now undefined or controlled by different code.
Attackers exploit this by orchestrating a three-step process: first, trigger the memory deallocation; second, cause the allocator to reassign that same memory region with attacker-controlled data (often through carefully timed allocations); third, trigger the program to dereference the dangling pointer. Because the memory now contains attacker data instead of the expected object, this can corrupt function pointers, vtables, or other critical structures.
The vulnerability is particularly dangerous in object-oriented code where freed objects contain function pointers or virtual method tables. When the program calls a method on the freed object, it may jump to attacker-controlled addresses. Browser engines are frequent targets because DOM manipulation allows attackers to control object allocation and deallocation timing through JavaScript, while kernel UAFs enable privilege escalation by manipulating file descriptors or process structures.
Impact
- Arbitrary code execution — attacker overwrites function pointers or vtables to redirect program flow to malicious code
- Privilege escalation — in kernel UAFs, gain root/system privileges by corrupting process credentials or security tokens
- Information disclosure — read sensitive data from reallocated memory that wasn't properly cleared
- Sandbox escape — break out of browser or application sandboxes by corrupting security-critical objects
- Denial of service — crash the application through memory corruption, though attackers typically aim for exploitation rather than simple crashes
Real-World Examples
CVE-2021-30551 affected Chrome's V8 JavaScript engine, where improper handling of JavaScript typed arrays created a use-after-free in object property management. Attackers could trigger object deletion while retaining references, then reallocate the memory with controlled data to achieve code execution within the renderer process.
Windows kernel vulnerabilities like CVE-2020-17087 involved use-after-free conditions in the Windows keyboard layout handling code. Attackers exploited race conditions in keyboard layout switching to free kernel objects while retaining references, then reallocated the memory with controlled structures to elevate privileges from user to SYSTEM level.
The WhatsApp vulnerability CVE-2019-11932 demonstrated UAF exploitation in media parsing code, where specially crafted GIF files triggered premature memory deallocation. Subsequent access to the freed buffers allowed remote code execution without user interaction beyond receiving the malicious file.
Mitigation
- Memory-safe languages — use Rust, Go, Swift, or other languages with automatic memory management
- Smart pointers — employ RAII patterns and reference counting (unique_ptr, shared_ptr in C++)
- AddressSanitizer (ASAN) — detect UAF during testing through instrumented builds
- Immediate pointer nullification — set pointers to NULL after free() to cause immediate crashes rather than exploitable conditions
- Garbage collection — languages with GC prevent manual memory management errors
- Control Flow Integrity (CFI) — limits exploit impact by validating function pointer targets
- Heap hardening — allocator metadata protection and delayed reuse policies increase exploitation difficulty
Recent CVEs (6847)
Use after free in WebRTC in Google Chrome prior to 111.0.5563.64 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in DevTools in Google Chrome prior to 111.0.5563.64 allowed a remote attacker who had convienced the user to engage in direct UI interaction to potentially exploit heap corruption via. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in Swiftshader in Google Chrome prior to 111.0.5563.64 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An arbitrary file upload vulnerability in the camera_upload.php component of PMB v7.4.6 allows attackers to execute arbitrary code via a crafted image file. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Use-after-free vulnerability exists in Kostac PLC Programming Software (Former name: Koyo PLC Programming Software) Version 1.6.9.0 and earlier. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
A flaw use after free in the Linux kernel integrated infrared receiver/transceiver driver was found in the way user detaching rc device. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.
A use-after-free vulnerability in WebCore::RenderLayer::updateDescendantDependentFlags in WebKitGTK before 2.36.8 allows attackers to execute code remotely. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A use-after-free vulnerability in WebCore::RenderLayer::repaintBlockSelectionGaps in WebKitGTK before 2.36.8 allows attackers to execute code remotely. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A use-after-free vulnerability in WebCore::RenderLayer::setNextSibling in WebKitGTK before 2.36.8 allows attackers to execute code remotely. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A use-after-free vulnerability in WebCore::RenderLayer::renderer in WebKitGTK before 2.36.8 allows attackers to execute code remotely. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A use-after-free vulnerability in WebCore::RenderLayer::addChild in WebKitGTK before 2.36.8 allows attackers to execute code remotely. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In binder_transaction_buffer_release of binder.c, there is a possible use after free due to improper input validation. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.
In several functions of the Android Linux kernel, there is a possible way to corrupt memory due to a use after free. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available.
In several functions of MediaCodec.cpp, there is a possible way to corrupt memory due to a use after free. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.
There is a use-after-free vulnerability in the Linux Kernel which can be exploited to achieve local privilege escalation. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.
A use after free issue was addressed with improved memory management. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
In the Linux kernel 6.0.8, there is a use-after-free in ntfs_trim_fs in fs/ntfs3/bitmap.c. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
In the Linux kernel 6.0.8, there is a use-after-free in inode_cgwb_move_to_attached in fs/fs-writeback.c, related to __list_del_entry_valid. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
In the Linux kernel 6.0.8, there is a use-after-free in run_unpack in fs/ntfs3/run.c, related to a difference between NTFS sector size and media sector size. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
Use after free in Prompts in Google Chrome prior to 110.0.5481.177 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in WebRTC in Google Chrome on Windows prior to 110.0.5481.177 allowed a remote attacker who convinced the user to engage in specific UI interactions to potentially exploit heap. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in Video in Google Chrome prior to 110.0.5481.177 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in Vulkan in Google Chrome prior to 110.0.5481.177 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in SwiftShader in Google Chrome prior to 110.0.5481.177 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in Web Payments API in Google Chrome on Android prior to 110.0.5481.177 allowed a remote attacker who had compromised the renderer process to potentially exploit heap corruption via a. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Adobe Animate versions 22.0.8 (and earlier) and 23.0.0 (and earlier) are affected by a Use After Free vulnerability that could result in arbitrary code execution in the context of the current user. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Adobe Premiere Rush version 2.6 (and earlier) is affected by a Use After Free vulnerability that could result in arbitrary code execution in the context of the current user. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
FrameMaker 2020 Update 4 (and earlier), 2022 (and earlier) are affected by a Use After Free vulnerability that could lead to disclosure of sensitive memory. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Due to a vulnerability in the io_uring subsystem, it is possible to leak kernel memory information to the user process. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.
.NET and Visual Studio Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.
Windows Graphics Component Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.
NT OS Kernel Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.
A vulnerability has been identified in Solid Edge SE2022 (All versions < V222.0MP12), Solid Edge SE2022 (All versions), Solid Edge SE2023 (All versions < V223.0Update2). Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
LibTIFF 4.4.0 has an out-of-bounds read in tiffcrop in tools/tiffcrop.c:3701, allowing attackers to cause a denial-of-service via a crafted tiff file. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. Public exploit code available.
Use-after free vulnerability exists in Screen Creator Advance 2 Ver.0.1.1.4 Build01 and earlier due to lack of error handling process even when an error was detected. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.
The public API function BIO_new_NDEF is a helper function used for streaming ASN.1 data via a BIO. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.
Use after free in GPU in Google Chrome prior to 110.0.5481.77 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page and browser shutdown. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In display drm, there is a possible use after free due to a race condition. Rated medium severity (CVSS 6.4). No vendor patch available.
The Linux kernel through 6.1.9 has a Use-After-Free in bigben_remove in drivers/hid/hid-bigbenff.c via a crafted USB device because the LED controllers remain registered for too long. Rated medium severity (CVSS 4.6), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
There is a logic error in io_uring's implementation which can be used to trigger a use-after-free vulnerability leading to privilege escalation. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.
Use after free in GuestView in Google Chrome prior to 109.0.5414.119 allowed an attacker who convinced a user to install a malicious extension to potentially exploit heap corruption via a Chrome web. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in WebRTC in Google Chrome prior to 109.0.5414.119 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in WebTransport in Google Chrome prior to 109.0.5414.119 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In binder_vma_close of binder.c, there is a possible use after free due to improper locking. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
In setUclampMinLocked of PowerSessionManager.cpp, there is a possible way to corrupt memory due to a use after free. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
In queue of UsbRequest.java, there is a possible way to corrupt memory due to a use after free. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
A use-after-free flaw was found in io_uring/poll.c in io_poll_check_events in the io_uring subcomponent in the Linux Kernel due to a race condition of poll_refs. Rated medium severity (CVSS 4.7). Public exploit code available and no vendor patch available.
Microsoft Edge (Chromium-based) Elevation of Privilege Vulnerability. Rated high severity (CVSS 8.3), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
Adobe Dimension version 3.4.6 (and earlier) are affected by a Use After Free vulnerability that could lead to disclosure of sensitive memory. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity.
Use After Free in GitHub repository gpac/gpac prior to 2.3.0-DEV. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. Public exploit code available.
Adobe InCopy versions 18.0 (and earlier), 17.4 (and earlier) are affected by a Use After Free vulnerability that could lead to disclosure of sensitive memory. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
A Use After Free vulnerability in the kernel of Juniper Networks Junos OS Evolved allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS). Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
3D Builder Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.
Windows Kernel Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Windows Kernel Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Windows Kernel Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Windows Kernel Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Microsoft Office Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Microsoft Office Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Microsoft DWM Core Library Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Windows Win32k Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Windows Layer 2 Tunneling Protocol (L2TP) Remote Code Execution Vulnerability. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
Windows GDI Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Microsoft Cryptographic Services Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Windows GDI Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.0). No vendor patch available.
Use after free in Cart in Google Chrome prior to 109.0.5414.74 allowed an attacker who convinced a user to install a malicious extension to potentially exploit heap corruption via database corruption. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in Cart in Google Chrome prior to 109.0.5414.74 allowed an attacker who convinced a user to install a malicious extension to potentially exploit heap corruption via database corruption. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in Overview Mode in Google Chrome on Chrome OS prior to 109.0.5414.74 allowed a remote attacker who convinced a user to engage in specific UI interactions to potentially exploit heap. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An issue was discovered in the Linux kernel 5.10.x before 5.10.155. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. Public exploit code available.
An issue was discovered in ksmbd in the Linux kernel 5.15 through 5.19 before 5.19.2. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.
A use-after-free in WebGL extensions could have led to a potentially exploitable crash. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A missing check related to tex units could have led to a use-after-free and potentially exploitable crash.<br />*Note*: This advisory was added on December 13th, 2022 after we better understood the. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The garbage collector could have been aborted in several states and zones and <code>GCRuntime::finishCollection</code> may not have been called, leading to a use-after-free and potentially. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
If an attacker loaded a font using <code>FontFace()</code> on a background worker, a use-after-free could have occurred, leading to a potentially exploitable crash. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
If an out-of-memory condition occurred when creating a JavaScript global, a JavaScript realm may be deleted while references to it lived on in a BaseShape. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Freeing arbitrary <code>nsIInputStream</code>'s on a different thread than creation could have led to a use-after-free and potentially exploitable crash. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Concurrent use of the URL parser with non-UTF-8 data was not thread-safe. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A data race could occur in the <code>PK11_ChangePW</code> function, potentially leading to a use-after-free vulnerability. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
The Mozilla Fuzzing Team reported potential vulnerabilities present in Thunderbird 91.10. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Session history navigations may have led to a use-after-free and potentially exploitable crash. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
By using a link with <code>rel="localization"</code> a use-after-free could have been triggered by destroying an object during JavaScript execution and then referencing the object through a freed. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
In unusual circumstances, an individual thread may outlive the thread's manager during shutdown. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
An attacker could have caused a use-after-free by forcing a text reflow in an SVG object leading to a potentially exploitable crash. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Certain network request objects were freed too early when releasing a network request handle. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
After a VR Process is destroyed, a reference to it may have been retained and used, leading to a use-after-free and potentially exploitable crash. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
<code>NSSToken</code> objects were referenced via direct points, and could have been accessed in an unsafe way on different threads, leading to a use-after-free and potentially exploitable crash. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Use after free vulnerability in CX-Drive V3.00 and earlier allows a local attacker to execute arbitrary code by having a user to open a specially crafted file,. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
The contacts component has a free (undefined) provider vulnerability. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.
In ServiceInterface::HandleRequest of serviceinterface.cpp, there is a possible use after free. Rated medium severity (CVSS 6.7), this vulnerability is low attack complexity. No vendor patch available.
In the Pixel camera driver, there is a possible use after free due to a logic error in the code. Rated medium severity (CVSS 6.7), this vulnerability is low attack complexity. No vendor patch available.