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Weakness · VariantCWE-122

CWE-122: Heap-based Buffer Overflow

Likelihood of exploit: HighKEV-linkedVariant

As of 2026-10-05, CWE-122 (Heap-based Buffer Overflow) underlies 54 CVEs tracked by Threadlinqs, 8 of them in the CISA Known Exploited Vulnerabilities catalog, and is cited by 62 tracked threats. MITRE rates its likelihood of exploit as High.

CVEs
54Mapped to CWE-122
CISA KEV
8Exploited in the wild
Critical
8CVSS v3 critical CVEs
Threats
62Tracked campaigns citing it
Likelihood
HighMITRE likelihood of exploit

Last updated:

What is CWE-122?

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

CWE-122 is a variant-level weakness in MITRE’s Common Weakness Enumeration, with a MITRE likelihood of exploit of High. Applicable platforms: Language: Memory-Unsafe; Language: C; Language: C++; Technology: Not Technology-Specific.

Source: MITRE CWE (CWE-122 definition, reproduced verbatim). Counts and linkage below are Threadlinqs data.

Consequences

  • Availability — DoS: Crash, Exit, or Restart, DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory). Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.
  • Integrity, Confidentiality, Availability, Access Control — Execute Unauthorized Code or Commands, Bypass Protection Mechanism, Modify Memory. Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of a program's implicit security policy. Besides important user data, heap-based overflows can be used to overwrite function pointers that may be living in memory, pointing it to the attacker's code. Even in applications that do not explicitly use function pointers, the run-time will usually leave many in memory. For example, object methods in C++ are generally implemented using function pointers…
  • Integrity, Confidentiality, Availability, Access Control, Other — Execute Unauthorized Code or Commands, Bypass Protection Mechanism, Other. When the consequence is arbitrary code execution, this can often be used to subvert any other security service.

Source: MITRE CWE, common consequences.

How CWE-122 is exploited in the wild

Threadlinqs maps 54 CVEs to CWE-122, published between 2009-10-13 and 2026-09-30. 8 are listed in CISA’s Known Exploited Vulnerabilities catalog, the authoritative record of exploitation in the wild, and 2 are tied to ransomware campaigns. By CVSS v3 severity the set splits into 8 critical, 35 high, 9 medium, 1 low. The highest EPSS score in the set is 90.9% (CVE-2023-27997), the modelled probability of exploitation in the next 30 days. 62 tracked threats reference CWE-122 directly or through a CVE it covers; the most recent is “Multiple High-Severity Vulnerabilities in TeamViewer Client (CVE-2026-92370, CVE-2026-92368, CVE-2026-92369, CVE-2026-92371, CVE-2026-19743)” (2026-10-02). Affected products concentrate in Microsoft (18), Google (6), F5 (4), among 23 vendors in total.

Vulnerabilities (CVEs)

Showing 40 of 54 CVEs mapped to CWE-122, CISA KEV first, then by CVSS score.

  • CVE-2023-27997 — CISA KEV · CVSS 9.8 critical · EPSS 90.9% · published 2023-06-13
  • CVE-2019-3568 — CISA KEV · CVSS 9.8 critical · EPSS 39.1% · published 2019-05-14
  • CVE-2026-94127 — CISA KEV · CVSS 9.8 critical · EPSS 1.3% · published 2026-09-22
  • CVE-2009-3459 — CISA KEV · CVSS 8.8 high · EPSS 88.0% · published 2009-10-13
  • CVE-2023-4911 — CISA KEV · CVSS 7.8 high · EPSS 81.4% · published 2023-10-03
  • CVE-2026-53362 — CISA KEV · CVSS 7.8 high · EPSS 0.5% · published 2026-07-04
  • CVE-2026-85880 — CISA KEV · CVSS 7.8 high · published 2026-09-08
  • CVE-2025-25249 — CISA KEV · CVSS 7.4 high · EPSS 1.6% · published 2026-01-13
  • CVE-2026-47291 — CVSS 9.8 critical · EPSS 21.5% · published 2026-06-09
  • CVE-2026-85103 — CVSS 9.8 critical · EPSS 0.3% · published 2026-09-09
  • CVE-2026-41096 — CVSS 9.8 critical · EPSS 0.0% · published 2026-05-12
  • CVE-2026-78510 — CVSS 9.8 critical · published 2026-09-08
  • CVE-2026-102331 — CVSS 9.6 critical · published 2026-09-29
  • CVE-2026-25589 — CVSS 8.8 high · EPSS 1.3% · published 2026-05-05
  • CVE-2026-69486 — CVSS 8.8 high · EPSS 0.6% · published 2026-09-15
  • CVE-2026-5858 — CVSS 8.8 high · EPSS 0.0% · published 2026-04-08
  • CVE-2026-4675 — CVSS 8.8 high · EPSS 0.0% · published 2026-03-24
  • CVE-2026-9119 — CVSS 8.8 high · EPSS 0.0% · published 2026-05-20
  • CVE-2026-40403 — CVSS 8.8 high · EPSS 0.0% · published 2026-05-12
  • CVE-2026-78505 — CVSS 8.8 high · published 2026-09-08
  • CVE-2026-40364 — CVSS 8.4 high · EPSS 0.1% · published 2026-05-12
  • CVE-2026-32190 — CVSS 8.4 high · EPSS 0.0% · published 2026-04-14
  • CVE-2026-40363 — CVSS 8.4 high · EPSS 0.0% · published 2026-05-12
  • CVE-2026-14427 — CVSS 8.3 high · published 2026-07-01
  • CVE-2026-42055 — CVSS 8.1 high · EPSS 1.8% · published 2026-06-17
  • CVE-2026-42945 — CVSS 8.1 high · EPSS 0.8% · published 2026-05-13
  • CVE-2026-9256 — CVSS 8.1 high · EPSS 0.1% · published 2026-05-22
  • CVE-2026-42980 — CVSS 7.8 high · EPSS 6.9% · published 2026-06-09
  • CVE-2023-40031 — CVSS 7.8 high · EPSS 0.3% · published 2023-08-25
  • CVE-2026-15506 — CVSS 7.8 high · EPSS 0.1% · published 2026-07-12
  • CVE-2026-35421 — CVSS 7.8 high · EPSS 0.0% · published 2026-05-12
  • CVE-2026-42831 — CVSS 7.8 high · EPSS 0.0% · published 2026-05-12
  • CVE-2026-90556 — CVSS 7.8 high · published 2026-09-12
  • CVE-2026-56208 — CVSS 7.6 high · published 2026-06-19
  • CVE-2026-42992 — CVSS 7.5 high · EPSS 0.4% · published 2026-06-09
  • CVE-2026-44799 — CVSS 7.5 high · EPSS 0.4% · published 2026-06-09
  • CVE-2026-42993 — CVSS 7.5 high · EPSS 0.4% · published 2026-06-09
  • CVE-2026-53994 — CVSS 7.5 high · EPSS 0.4% · published 2026-07-18
  • CVE-2026-67867 — CVSS 7.5 high · EPSS 0.2% · published 2026-08-05
  • CVE-2026-68580 — CVSS 7.5 high · EPSS 0.2% · published 2026-08-02

Affected vendors

Threat activity

62 tracked threats cite CWE-122; the 25 most recent are listed.

Mitigations

  • General: Pre-design: Use a language or compiler that performs automatic bounds checking.
  • Architecture and Design: Use an abstraction library to abstract away risky APIs. Not a complete solution.
  • Operation, Build and Compilation / Environment Hardening: Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
  • Operation, Build and Compilation / Environment Hardening: Run or compile the software using features or extensions that randomly arrange the positions of a program's executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code. Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as "rebasing" (for Windows) and "prelinking" (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would…
  • Implementation: Implement and perform bounds checking on input.
  • Implementation / Libraries or Frameworks: Do not use dangerous functions such as gets. Look for their safe equivalent, which checks for the boundary.
  • Operation: Use OS-level preventative functionality. This is not a complete solution, but it provides some defense in depth.

Source: MITRE CWE, potential mitigations.

Detection methods (MITRE CWE)

  • Fuzzing (effectiveness: High): Fuzz testing (fuzzing) is a powerful technique for generating large numbers of diverse inputs - either randomly or algorithmically - and dynamically invoking the code with those inputs. Even with random inputs, it is often capable of generating unexpected results such as crashes, memory corruption, or resource consumption. Fuzzing effectively produces repeatable test cases that clearly indicate bugs, which helps developers to diagnose the issues.
  • Automated Dynamic Analysis (effectiveness: Moderate): Use tools that are integrated during compilation to insert runtime error-checking mechanisms related to memory safety errors, such as AddressSanitizer (ASan) for C/C++ [REF-1518].

Source: MITRE CWE, detection methods. Threadlinqs detection rules for the threats above are Blue tier and higher.