---
id: CVE-2026-76957
title: >-
  libexpat before 2.8.4 lacks handler call depth tracking with custom encoding
  callbacks
summary: >-
  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.
severity: medium
cvss: 4.9
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-416
  - CWE-825
vendor: libexpat_project
product: libexpat
affected:
  - libexpat < 2.8.4
patched:
  - libexpat 2.8.4
published: '2026-08-20'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T20:56:31.860'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-76957'
references:
  - url: 'https://github.com/libexpat/libexpat/pull/1322'
    label: cve@mitre.org
  - url: 'https://github.com/libexpat/libexpat/pull/1329'
    label: cve@mitre.org
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-76957.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-76957'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2520125'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-76957'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-76957'
  - url: 'https://access.redhat.com/errata/RHSA-2026:60451'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.00148
epssPercentile: 0.03323
ingestedAt: '2026-09-08T21:11:12.284Z'
---

## Overview

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.

## Affected

- `libexpat < 2.8.4`

## Remediation

Upgrade past the affected range:

- `libexpat 2.8.4`

## Vendor advisories

- **RHSA-2026:60451** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-08-27 · [advisory](https://access.redhat.com/errata/RHSA-2026:60451)
- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-08 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-76957.json)