Raw vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:LSummary
CVE-2026-56405 is a medium-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Libexpat Project Libexpat. Its CVSS base score is 6.9 (Medium).
Operationally, ranked at the 3th 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 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-38182
Vulnerability Data
libexpat before 2.8.2 has an integer overflow in getAttributeId.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Insufficient information to map techniques.CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly requires timely patching or upgrading of libexpat to version 2.8.2 or later to eliminate the integer overflow in getAttributeId.
Enforces validation of all input data (including XML attribute lengths and values) before processing, blocking the malformed inputs that trigger the CWE-190 overflow.
Requires integrity checks on software and parsed data, enabling detection of corruption or anomalous behavior resulting from exploitation of the overflow.
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.