Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-76957

CVE-2026-76957HIGH

libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks.

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  H  H  H    7.8   .0011    1.0     —

AFFECTED
  Product   Versions     Fixed
  libexpat  unspecified  —

TIMELINE
  Aug 20  Reserved by mitre
  Aug 20  Published (CNA: mitre)
  Sep 8   RESCORED — CVE-2026-76957 (libexpat project libexpat). CVSS 4.9 → 7.8 (NVD).

CWE-416 · CNA: mitre · CVSS v3.1 · 2 references · NVD status: Analyzed

Description

libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
August 20, 2026	Reserved	Reserved by mitre
August 20, 2026	Published	Published (CNA: mitre)
September 8, 2026	RESCORED	RESCORED — CVE-2026-76957 (libexpat project libexpat). CVSS 4.9 → 7.8 (NVD).

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
libexpat project	libexpat	—	—	—

Weaknesses

CWE-416

References (2)

https://github.com/libexpat/libexpat/pull/1322 [Issue Tracking, Patch, Vendor Advisory]
https://github.com/libexpat/libexpat/pull/1329 [Issue Tracking, Patch]

Authoritative record: CVE-2026-76957 at cve.org

Vendors: libexpat project

Weaknesses: CWE-416

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-76957 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.