Denial of Service
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
How It Works
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions. Attackers exploit asymmetry: minimal attacker effort produces disproportionate resource consumption on the target. Application-level attacks use specially crafted inputs that trigger expensive operations—a regex engine processing malicious patterns can backtrack exponentially, or XML parsers recursively expand entities until memory exhausts. Network-level attacks flood targets with connection requests or amplify traffic through reflection, but application vulnerabilities often provide the most efficient attack surface.
The attack typically begins with reconnaissance to identify resource-intensive operations or unprotected endpoints. For algorithmic complexity attacks, adversaries craft inputs hitting worst-case performance—hash collision inputs filling hash tables with collisions, deeply nested JSON triggering recursive parsing, or pathological regex patterns like (a+)+b against strings of repeated 'a' characters. Resource exhaustion attacks open thousands of connections, upload massive files to unbounded storage, or trigger memory leaks through repeated operations. Crash-based attacks target error handling gaps: null pointer dereferences, unhandled exceptions in parsers, or assertion failures that terminate processes.
Impact
- Service unavailability preventing legitimate users from accessing applications during attack duration
- Revenue loss from downtime in e-commerce, SaaS platforms, or transaction processing systems
- Cascading failures as resource exhaustion spreads to dependent services or database connections pool out
- SLA violations triggering financial penalties and damaging customer trust
- Security team distraction providing cover for data exfiltration or intrusion attempts running concurrently
Real-World Examples
CVE-2018-1000544 in Ruby's WEBrick server allowed ReDoS through malicious HTTP headers containing specially crafted patterns that caused the regex engine to backtrack exponentially, freezing request processing threads. A single attacker could saturate all available workers.
Cloudflare experienced a global outage in 2019 when a single WAF rule containing an unoptimized regex hit pathological cases on legitimate traffic spikes. The .*(?:.*=.*)* pattern exhibited catastrophic backtracking, consuming CPU cycles across their edge network until the rule was disabled.
CVE-2013-1664 demonstrated XML bomb vulnerabilities in Python's XML libraries. Attackers uploaded XML documents with nested entity definitions-each entity expanding to ten copies of the previous level. A 1KB upload could expand to gigabytes in memory during parsing, crashing applications instantly.
Mitigation
- Strict input validation enforcing size limits, complexity bounds, and nesting depth restrictions before processing
- Request rate limiting per IP address, API key, or user session with exponential backoff
- Timeout enforcement terminating operations exceeding reasonable execution windows (typically 1-5 seconds)
- Resource quotas limiting memory allocation, CPU time, and connection counts per request or tenant
- Regex complexity analysis using linear-time algorithms or sanitizing patterns to eliminate backtracking
- Circuit breakers automatically rejecting requests when error rates or latency thresholds indicate degradation
- Load balancing and autoscaling distributing traffic across instances with automatic capacity expansion
Recent CVEs (36866)
In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Add NULL pointer checks in dc_stream cursor attribute functions The function dc_stream_set_cursor_attributes(). No vendor patch available.
Linux kernel block I/O throttling subsystem crashes with a NULL pointer dereference when I/O operations are submitted during early initialization before throttle policy is fully activated, causing denial of service on affected systems. The vulnerability affects the block layer's throttle policy initialization sequence and is triggered sporadically on cold boots when blk_should_throtl() accesses uninitialized throttle group state. With an EPSS score of 0.03% (10th percentile) and no public exploit identified, this is a low-probability but high-impact local crash condition requiring a kernel patch to fully resolve.
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid NULL pointer dereference in f2fs_check_quota_consistency() syzbot reported a f2fs bug as below: Oops: gen[. No vendor patch available.
In the Linux kernel, the following vulnerability has been resolved: dm: fix NULL pointer dereference in __dm_suspend() There is a race condition between dm device suspend and table load that can lead.
In the Linux kernel, the following vulnerability has been resolved: sunrpc: fix null pointer dereference on zero-length checksum In xdr_stream_decode_opaque_auth(), zero-length checksum.len causes.
In the Linux kernel, the following vulnerability has been resolved: bpf: Enforce expected_attach_type for tailcall compatibility Yinhao et al.
In the Linux kernel, the following vulnerability has been resolved: ext4: fix potential null deref in ext4_mb_init() In ext4_mb_init(), ext4_mb_avg_fragment_size_destroy() may be called when sbi->s_mb_avg_fragment_size remains uninitialized (e.g., if groupinfo slab cache allocation fails). Since ext4_mb_avg_fragment_size_destroy() lacks null pointer checking, this leads to a null pointer dereference. ================================================================== EXT4-fs: no memory for groupinfo slab cache BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 0 P4D 0 Oops: Oops: 0002 [#1] SMP PTI CPU:2 UID: 0 PID: 87 Comm:mount Not tainted 6.17.0-rc2 #1134 PREEMPT(none) RIP: 0010:_raw_spin_lock_irqsave+0x1b/0x40 Call Trace: <TASK> xa_destroy+0x61/0x130 ext4_mb_init+0x483/0x540 __ext4_fill_super+0x116d/0x17b0 ext4_fill_super+0xd3/0x280 get_tree_bdev_flags+0x132/0x1d0 vfs_get_tree+0x29/0xd0 do_new_mount+0x197/0x300 __x64_sys_mount+0x116/0x150 do_syscall_64+0x50/0x1c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e ================================================================== Therefore, add necessary null check to ext4_mb_avg_fragment_size_destroy() to prevent this issue. The same fix is also applied to ext4_mb_largest_free_orders_destroy().
In the Linux kernel, the following vulnerability has been resolved: scsi: mpt3sas: Fix crash in transport port remove by using ioc_info() During mpt3sas_transport_port_remove(), messages were logged.
In the Linux kernel, the following vulnerability has been resolved: remoteproc: qcom: pas: Shutdown lite ADSP DTB on X1E The ADSP firmware on X1E has separate firmware binaries for the main firmware. No vendor patch available.
In the Linux kernel, the following vulnerability has been resolved: sparc: fix accurate exception reporting in copy_{from_to}_user for Niagara The referenced commit introduced exception handlers on.
Substance3D - Stager versions 3.1.5 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.
Substance3D - Stager versions 3.1.5 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.
A flaw was discovered in libvirt in the XML file processing. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
Format Plugins versions 1.1.1 and earlier are affected by a Use After Free vulnerability that could lead to memory exposure. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Use after free in Microsoft Office allows an unauthorized attacker to execute code locally. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally. Rated high severity (CVSS 7.0). No vendor patch available.
Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locally. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code locally. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Use after free in Microsoft Office allows an unauthorized attacker to execute code locally. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Use after free in Windows Broadcast DVR User Service allows an authorized attacker to elevate privileges locally. Rated high severity (CVSS 7.0). No vendor patch available.
Use after free in Windows DirectX allows an authorized attacker to elevate privileges locally. Rated high severity (CVSS 7.0). No vendor patch available.
Use after free in Multimedia Class Scheduler Service (MMCSS) allows an authorized attacker to elevate privileges locally. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Use after free in Windows Broadcast DVR User Service allows an authorized attacker to elevate privileges locally. Rated high severity (CVSS 7.0). No vendor patch available.
InCopy versions 20.5, 19.5.5 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.
InCopy versions 20.5, 19.5.5 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.
InDesign Desktop versions 20.5, 19.5.5 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.
InDesign Desktop versions 20.5, 19.5.5 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.
Out-of-bounds write for some Intel(R) PROSet/Wireless WiFi Software for Windows before version 23.160 within Ring 2: Device Drivers may allow a denial of service. Rated high severity (CVSS 8.3), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Out-of-bounds read for some Intel(R) PROSet/Wireless WiFi Software for Windows before version 23.160 within Ring 2: Device Drivers may allow a denial of service. Rated high severity (CVSS 7.0), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Insufficient control flow management for some Intel(R) PROSet/Wireless WiFi Software for Windows before version 23.160 within Ring 2: Device Drivers may allow a denial of service. Rated high severity (CVSS 8.3), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
NVIDIA Triton Inference Server for Linux and Windows contains a vulnerability where an attacker could cause a stack overflow by sending extra-large payloads. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Out-of-bounds write for some Intel(R) PROSet/Wireless WiFi Software for Windows before version 23.160 within Ring 2: Device Drivers may allow a denial of service. Rated high severity (CVSS 8.3), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Buffer overflow for some Intel(R) QAT Windows software before version 2.6.0. Rated medium severity (CVSS 5.8), this vulnerability is low attack complexity. No vendor patch available.
Improper conditions check for some Intel(R) QAT Windows software before version 2.6.0. Rated medium severity (CVSS 4.8), this vulnerability is low attack complexity. No vendor patch available.
Improper access control for some Intel(R) PresentMon before version 2.3.1 within Ring 3: User Applications may allow a denial of service. Rated low severity (CVSS 2.0). No vendor patch available.
Improper input validation for some Intel(R) oneAPI Math Kernel Library before version 2025.2 within Ring 3: User Applications may allow a denial of service. Rated medium severity (CVSS 4.8), this vulnerability is low attack complexity. No vendor patch available.
Out-of-bounds read for some Intel(R) QAT Windows software before version 2.6.0. Rated medium severity (CVSS 5.7). No vendor patch available.
Time-of-check time-of-use race condition for some Intel Ethernet Adapter Complete Driver Pack software before version 1.5.1.0 within Ring 3: User Applications may allow a denial of service. Rated medium severity (CVSS 5.1), this vulnerability is low attack complexity. No vendor patch available.
Out-of-bounds write for some Intel(R) PROSet/Wireless WiFi Software for Windows before version 23.160 within Ring 2: Device Drivers may allow a denial of service. Rated high severity (CVSS 8.3), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Active debug code for some Intel UEFI reference platforms within Ring 0: Kernel may allow a denial of service and escalation of privilege. Rated high severity (CVSS 8.3), this vulnerability is low attack complexity. No vendor patch available.
Time-of-check time-of-use race condition for some ACAT before version 3.13 within Ring 3: User Applications may allow a denial of service. Rated medium severity (CVSS 4.1). No vendor patch available.
Uncontrolled resource consumption for some Gaudi software before version 1.21.0 within Ring 3: User Applications may allow a denial of service. Rated medium severity (CVSS 6.8), this vulnerability is low attack complexity. No vendor patch available.
Null pointer dereference for some Intel(R) QAT Windows software before version 2.6.0. Rated medium severity (CVSS 6.8), this vulnerability is low attack complexity. No vendor patch available.
Improper control of dynamically-managed code resources for some Intel(R) NPU Drivers within Ring 3: User Applications may allow a denial of service. Rated medium severity (CVSS 5.1), this vulnerability is low attack complexity. No vendor patch available.
Protection mechanism failure for some Intel(R) NPU Drivers within Ring 3: User Applications may allow a denial of service. Rated medium severity (CVSS 6.8), this vulnerability is low attack complexity. No vendor patch available.
Improper input validation in some firmware for some Intel(R) Graphics Drivers and Intel LTS kernels within Ring 1: Device Drivers may allow a denial of service. Rated low severity (CVSS 2.0), this vulnerability is low attack complexity. No vendor patch available.
Improper input validation for some Intel(R) PROSet/Wireless WiFi Software for Windows before version 23.160 within Ring 2: Device Drivers may allow a denial of service. Rated medium severity (CVSS 5.7). No vendor patch available.
The VAPIX API port.cgi did not have sufficient input validation, which may result in process crashes and impact usability. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
It was possible to upload files with a specific name to a temporary directory, which may result in process crashes and impact usability. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
The Crypto plugin for WordPress is vulnerable to unauthorized manipulation of data in all versions up to, and including, 2.22. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
SpiceDB is an open source database system for creating and managing security-critical application permissions. Rated low severity (CVSS 2.7), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Allocation of Resources Without Limits vulnerability could allow attackers to exhaust system resources through uncontrolled allocation.
Bugsink is a self-hosted error tracking tool. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Bugsink is a self-hosted error tracking tool. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. Rated low severity (CVSS 2.0), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Tenda AX3 V16.03.12.10_CN was discovered to contain a stack overflow in the urls parameter of the get_parentControl_list_Info function. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Use after free in Ozone in Google Chrome on Linux and ChromeOS prior to 142.0.7444.59 allowed a remote attacker to potentially exploit object 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 PageInfo in Google Chrome prior to 142.0.7444.59 allowed a remote attacker who convinced a user to engage in specific UI gestures to potentially exploit heap corruption via a. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
In Open5GS 2.7.6, AMF crashes when receiving an abnormal NGSetupRequest message, resulting in denial of service. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Uncontrolled Resource Consumption vulnerability could allow attackers to cause denial of service by exhausting system resources.
A stack-based buffer overflow vulnerability was discovered in Tenda AC18 v15.03.05.05_multi. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Tenda AX-1803 v1.0.0.1 was discovered to contain a stack overflow via the wanMTU parameter in the sub_4F55C function. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Tenda AX-1803 v1.0.0.1 was discovered to contain a stack overflow via the time parameter in the SetSysTimeCfg function. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Tenda AX-3 v16.03.12.10_CN was discovered to contain a stack overflow via the shareSpeed parameter in the fromSetWifiGusetBasic function. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Tenda AX3 V16.03.12.10_CN was discovered to contain a stack overflow in the deviceId parameter of the saveParentControlInfo function. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
TOTOLink A7000R V9.1.0u.6115_B20201022 was discovered to contain a stack overflow in the addEffect parameter of the urldecode function. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
TOTOLink A7000R V9.1.0u.6115_B20201022 was discovered to contain a stack overflow in the ssid parameter of the urldecode function. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Tenda AX3 V16.03.12.10_CN was discovered to contain a stack overflow in the wpapsk_crypto parameter of the wlSetExternParameter function. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
NULL pointer dereference vulnerability exists in GNU libmicrohttpd v1.0.2 and earlier. Rated high severity (CVSS 8.7), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
NULL pointer dereference vulnerability exists in GNU libmicrohttpd v1.0.2 and earlier. Rated high severity (CVSS 8.7), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
A vulnerability was identified in TOZED ZLT T10 T10PLUS_3.04.15. Rated medium severity (CVSS 5.3), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Potential Denial of Service issue in all supported versions of Revenera InstallShield version 2025 R1, 2024 R2, 2023 R2, and prior. Rated medium severity (CVSS 5.6), this vulnerability is low attack complexity. No vendor patch available.
Improper resource management in firmware of some Solidigm DC Products may allow an attacker with local or physical access to gain un-authorized access to a locked Storage Device or create a Denial of. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
A flaw was found in FFmpeg’s ALS audio decoder, where it does not properly check for memory allocation failures. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
IBM Db2 12.1.0 through 12.1.2 for Linux, UNIX and Windows (includes Db2 Connect Server) could allow a local user to cause a denial of service due to improper neutralization of special elements in. Rated medium severity (CVSS 6.2), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
IBM Db2 11.5.0 through 11.5.9, and 12.1.0 through 12.1.3 for Linux, UNIX and Windows (includes DB2 Connect Server) could allow a local user to cause a denial of service due to the database monitor. Rated medium severity (CVSS 5.1), this vulnerability is no authentication required. No vendor patch available.
IBM Db2 11.5.0 through 11.5.9, and 12.1.0 through 12.1.3 for Linux, UNIX and Windows (includes Db2 Connect Server) could allow an authenticated user to cause a denial of service due to improper. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
IBM Db2 11.1.0 through 11.1.4.7, 11.5.0 through 11.5.9, and 12.1.0 through 12.1.3 for Linux, UNIX and Windows (includes Db2 Connect Server) is vulnerable to a denial of service as the server may. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable. No vendor patch available.
Improper handling of malformed Connection Request with the interval set to be 1 (which supposed to be illegal) and the chM 0x7CFFFFFFFF triggers a crash. Rated medium severity (CVSS 6.5), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
IBM Db2 10.5.0 through 10.5.11, 11.1.0 through 11.1.4.7, 11.5.0 through 11.5.9, and 12.1.0 through 12.1.3 for Linux, UNIX and Windows (includes Db2 Connect Server) is vulnerable to a denial of. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
An allocation of resources without limits or throttling vulnerability has been reported to affect File Station 5. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A NULL pointer dereference vulnerability has been reported to affect File Station 5. Rated low severity (CVSS 0.6), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
An allocation of resources without limits or throttling vulnerability has been reported to affect File Station 5. Rated low severity (CVSS 1.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
An allocation of resources without limits or throttling vulnerability has been reported to affect File Station 5. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
An allocation of resources without limits or throttling vulnerability has been reported to affect File Station 5. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A NULL pointer dereference vulnerability has been reported to affect File Station 5. Rated low severity (CVSS 1.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A NULL pointer dereference vulnerability has been reported to affect File Station 5. Rated low severity (CVSS 1.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A NULL pointer dereference vulnerability has been reported to affect several product versions. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Use after free in Safe Browsing in Google Chrome prior to 141.0.7390.107 allowed a remote attacker who had compromised the renderer process to potentially perform out of bounds memory access via a. 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 Storage in Google Chrome prior to 141.0.7390.65 allowed a remote attacker to execute arbitrary code via a crafted video file. 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 V8 in Google Chrome prior to 141.0.7390.54 allowed a remote attacker to potentially perform out of bounds memory access via a crafted HTML page. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
runc is a CLI tool for spawning and running containers according to the OCI specification. Rated high severity (CVSS 8.4), this vulnerability is no authentication required, low attack complexity. Public exploit code available.