Cyber Resilience

CVE-2026-56132

Libexpat Project Libexpat ≤ 2.8.2

Published
19 June 2026
Modified
23 June 2026
Patch / advisory
View advisory
CVSS Score v3.1 6.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
EPSS Score 0.0011 1th percentile
Risk Priority 48 floored blend · peak EPSS

Summary

CVE-2026-56132 is a medium-severity Incorrect Synchronization (CWE-821) 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 1th 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 SC-4 (Information in Shared System Resources) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

In libexpat before 2.8.2, there is a heap-based buffer overflow in doProlog in xmlparse.c because scaffold backing array reallocation is mishandled when there is data-structure sharing across parsers.

CWE(s)
CWE-821

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-45492Same product: Libexpat Project Libexpat
CVE-2026-25210Same product: Libexpat Project Libexpat
CVE-2026-56404Same product: Libexpat Project Libexpat
CVE-2026-56407Same product: Libexpat Project Libexpat
CVE-2026-56403Same product: Libexpat Project Libexpat
CVE-2026-56405Same product: Libexpat Project Libexpat
CVE-2026-56410Same product: Libexpat Project Libexpat
CVE-2026-56406Same product: Libexpat Project Libexpat
CVE-2026-56408Same product: Libexpat Project Libexpat
CVE-2026-56411Same product: Libexpat Project Libexpat

Affected Assets

libexpat project
libexpat
≤ 2.8.2

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SC-4 Information in Shared System Resources partial match

SC-4 directly requires preventing unintended information transfer through shared resources, structurally blocking the concurrent unsynchronized access described by CWE-821.

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.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require correct concurrency controls and synchronization primitives to prevent race conditions.

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.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect synchronization flaws before production deployment.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC practices include concurrency and synchronization requirements that reduce race conditions.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate proper locking and thread-safety controls.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles address concurrent access and resource synchronization.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly require correct synchronization primitives and thread-safety.

A.8.32 Change management none match
none

Change management processes can introduce or miss synchronization fixes during updates.

References