Raw vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:LSummary
CVE-2026-25210 is a medium-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Libexpat Project Libexpat. Its CVSS base score is 6.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-25210 is an integer overflow vulnerability (CWE-190) in the doContent function of libexpat versions prior to 2.7.4. The issue arises because there is no integer overflow check during tag buffer reallocation, leading to an improper determination of the buffer size bufSize. This flaw was published on 2026-01-30 and carries a CVSS v3.1 base score of 6.9 (Medium), with vector AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L.
A local attacker with no privileges required can exploit this vulnerability, though it demands high attack complexity and no user interaction. Successful exploitation allows high-impact confidentiality and integrity violations, such as unauthorized data disclosure or modification, alongside low availability disruption within the unchanged scope.
Mitigation is addressed in libexpat via the patch merged in pull request #1075, including the specific commit 9c2d990389e6abe2e44527eeaa8b39f16fe859c7. Security practitioners should upgrade affected libexpat instances to version 2.7.4 or later to resolve the integer overflow.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-5042
Vulnerability Data
In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.2.6
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (static analysis, fuzzing, unit tests) directly finds integer overflow defects before deployment.
Secure engineering principles require use of safe arithmetic constructs or language features that structurally eliminate integer overflow during calculation.
Input validation enforces bounds on values before arithmetic, stopping the conditions that trigger overflow or wraparound.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require use of safe arithmetic, bounds checks, and testing that prevent integer overflows.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development can detect integer overflows before release.
Secure SDLC mandates input validation and arithmetic checks that prevent integer overflows.
Application security requirements include bounds checking and safe arithmetic to avoid overflow conditions.
Secure architecture principles require defensive coding patterns that mitigate integer wraparound risks.
Secure coding standards explicitly forbid unsafe integer operations and mandate overflow-safe constructs.