Buffer Overflow
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
How It Works
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions. This overwrites whatever data or code exists there, corrupting program state and potentially giving attackers control over execution flow.
Stack-based overflows are the most common variant. When a function allocates a fixed-size buffer on the stack and then copies user-controlled input without proper bounds checking, attackers can overflow past the buffer to overwrite the function's return address. When the function completes, instead of returning to legitimate code, execution jumps to attacker-specified memory containing malicious shellcode. Heap-based overflows work differently—they corrupt heap metadata like chunk size fields or free list pointers, leading to arbitrary memory writes when the allocator processes the corrupted structures.
Modern exploitation bypasses defensive mechanisms through techniques like Return-Oriented Programming (ROP), which chains together existing code snippets to avoid non-executable memory protections. Attackers may also use heap spraying to reliably position shellcode at predictable addresses, defeating address randomization.
Impact
- Remote code execution — attacker gains ability to run arbitrary commands with the privileges of the vulnerable process
- Privilege escalation — exploiting kernel or setuid program overflows to gain root/SYSTEM access
- Denial of service — crashes and memory corruption that render systems unusable
- Information disclosure — reading sensitive data from adjacent memory regions that should be inaccessible
- Authentication bypass — overwriting security-critical variables like permission flags or user IDs
Real-World Examples
Fortinet FortiOS suffered a critical buffer overflow (CVE-2025-32756) that allowed unauthenticated remote attackers to execute code as root on firewalls and VPN gateways. Attackers actively exploited this to compromise enterprise network perimeters before patches were available.
The Slammer worm from 2003 exploited a stack overflow in Microsoft SQL Server, spreading to 75,000 hosts in ten minutes by sending a single malformed UDP packet that overwrote the return address with shellcode. No authentication was required.
OpenSSH historically contained a heap overflow in challenge-response authentication that allowed pre-authentication remote root compromise on Unix systems, demonstrating how memory corruption in privileged network services creates maximum impact scenarios.
Mitigation
- Memory-safe languages — Rust, Go, and modern managed languages prevent buffer overflows by design through automatic bounds checking
- Stack canaries — random values placed before return addresses that detect corruption before control transfer
- Address Space Layout Randomization (ASLR) — randomizes memory locations making exploitation less reliable
- Data Execution Prevention (DEP/NX) — marks memory regions as non-executable, preventing direct shellcode execution
- Bounds checking — validate input sizes before copying, use safe functions like
strncpyinstead ofstrcpy - Fuzzing and static analysis — automated testing to discover overflows before deployment
Recent CVEs (36390)
Windows Graphics Component Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.
Windows CSC Service Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.
Windows CSC Service Information Disclosure Vulnerability. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Microsoft Office Visio Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Hyper-V NT Kernel Integration VSP contains a heap-based buffer overflow allowing authorized local attackers to escalate privileges, one of three Hyper-V zero-days exploited in January 2025 Patch Tuesday.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Microsoft Message Queuing (MSMQ) Denial of Service Vulnerability. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Epss exploitation probability 30.3%.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Cloud Files Mini Filter Driver Elevation of Privilege Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows WLAN AutoConfig Service Information Disclosure Vulnerability. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Digital Media Elevation of Privilege Vulnerability. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Windows Telephony Service Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Secure Boot Security Feature Bypass Vulnerability. Rated medium severity (CVSS 4.6), this vulnerability is no authentication required, low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
Microsoft Access Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity.
Visual Studio Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
.NET, .NET Framework, and Visual Studio Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
.NET and Visual Studio Remote Code Execution Vulnerability. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
.NET Remote Code Execution Vulnerability. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
An out-of-bounds write in Ivanti EPM before the 2024 January-2025 Security Update and 2022 SU6 January-2025 Security Update allows a remote unauthenticated attacker to cause a denial of service. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An out-of-bounds read in Ivanti EPM before the 2024 January-2025 Security Update and 2022 SU6 January-2025 Security Update allows a local authenticated attacker to escalate their privileges. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
An out-of-bounds write in Ivanti EPM before the 2024 January-2025 Security Update and 2022 SU6 January-2025 Security Update allows a remote unauthenticated attacker to cause a denial of service. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An out-of-bounds write in Ivanti EPM before the 2024 January-2025 Security Update and 2022 SU6 January-2025 Security Update allows a remote unauthenticated attacker to cause a denial of service. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An out-of-bounds write in Ivanti EPM before the 2024 January-2025 Security Update and 2022 SU6 January-2025 Security Update allows a remote unauthenticated attacker to cause a denial of service. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An out-of-bounds write in Ivanti EPM before the 2024 January-2025 Security Update and 2022 SU6 January-2025 Security Update allows a remote unauthenticated attacker to cause a denial of service. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Multiple buffer overflow vulnerabilities exist in the qos.cgi qos_settings() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Multiple buffer overflow vulnerabilities exist in the qos.cgi qos_settings() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Multiple buffer overflow vulnerabilities exist in the qos.cgi qos_settings() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A buffer overflow vulnerability exists in the adm.cgi set_sys_adm() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Multiple buffer overflow vulnerabilities exist in the internet.cgi set_qos() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Multiple buffer overflow vulnerabilities exist in the internet.cgi set_qos() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Multiple buffer overflow vulnerabilities exist in the internet.cgi set_qos() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A stack-based buffer overflow vulnerability exists in the wireless.cgi AddMac() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A buffer overflow vulnerability exists in the adm.cgi rep_as_router() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A stack-based buffer overflow vulnerability exists in the wireless.cgi set_wifi_basic_mesh() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
An arbitrary code execution vulnerability exists in the adm.cgi set_MeshAp() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A stack-based buffer overflow vulnerability exists in the wireless.cgi DeleteMac() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A buffer overflow vulnerability exists in the adm.cgi set_wzap() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A stack-based buffer overflow vulnerability exists in the wireless.cgi SetName() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A buffer overflow vulnerability exists in the qos.cgi qos_sta_settings() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A buffer overflow vulnerability exists in the adm.cgi set_wzdgw4G() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A buffer overflow vulnerability exists in the internet.cgi set_add_routing() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and EPSS exploitation probability 14.8%.
A buffer overflow vulnerability exists in the adm.cgi set_TR069() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and EPSS exploitation probability 14.4%.
A buffer overflow vulnerability exists in the adm.cgi rep_as_bridge() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A stack-based buffer overflow vulnerability exists in the wireless.cgi set_wifi_basic() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A buffer overflow vulnerability exists in the login.cgi Goto_chidx() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 10.0), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
A buffer overflow vulnerability exists in the usbip.cgi set_info() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A stack-based buffer overflow vulnerability exists in the touchlist_sync.cgi touchlistsync() functionality of Wavlink AC3000 M33A8.V5030.210505. Rated critical severity (CVSS 10.0), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and EPSS exploitation probability 16.5%.
A out-of-bounds write in Fortinet FortiOS versions 7.6.0, 7.4.0 through 7.4.6, 7.2.0 through 7.2.10, 7.0.0 through 7.0.16, 6.4.0 through 6.4.15 allows attacker to trigger a denial of service via. Rated low severity (CVSS 3.7), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
An Out-of-bounds Read vulnerability [CWE-125] in FortiOS version 7.6.0, version 7.4.4 and below, version 7.2.9 and below and FortiSASE FortiOS tenant version 24.3.b IPsec IKE service may allow an. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An out-of-bounds read vulnerability [CWE-125] in FortiOS SSLVPN web portal versions 7.4.0 through 7.4.4, versions 7.2.0 through 7.2.8, 7.0 all verisons, and 6.4 all versions may allow an. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Remote code execution in Fortinet FortiManager and FortiAnalyzer (plus their Cloud variants) arises from a stack-based buffer overflow (CWE-121) reachable via specially crafted packets, letting an attacker run unauthorized code or OS commands on the management appliance. Affected trains span 6.4, 7.0, 7.2, and 7.4 across on-prem and Cloud editions. The CVSS vector rates this 9.8 with PR:N (network, no authentication), though the low EPSS (0.17%, 38th percentile) and absence of KEV/POC signals indicate no public exploit identified at time of analysis despite the critical rating.
A out-of-bounds write in Fortinet FortiManager version 7.4.0 through 7.4.2, FortiAnalyzer version 7.4.0 through 7.4.2 allows attacker to escalation of privilege via specially crafted http requests. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A stack-based buffer overflow in Fortinet FortiWeb versions 7.2.0 through 7.2.7, and 7.4.0 through 7.4.1 may allow a privileged user to execute arbitrary code via specially crafted CLI commands,. Rated medium severity (CVSS 6.4). No vendor patch available.
When switching to other buffers using the :all command and visual mode still being active, this may cause a heap-buffer overflow, because Vim does not properly end visual mode and therefore may try. Rated medium severity (CVSS 4.2).
An issue was discovered in Samsung Mobile Processor Exynos 9820, 9825, 980, 990, 850, 1080, 2100, and 1280. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.