CVE-2026-76957

libexpat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service

Published Aug 20, 2026 CVSS 3.1 · 4.9 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Debian DLA Debian DLA DLA-4765-1 expat security update
Debian DSA Debian DSA DSA-6566-1 expat security update
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Title Use-After-Free in libexpat Due to Missing Handler Depth Tracking for Custom Encoding Callbacks libexpat: libexpat: Memory corruption vulnerability allows arbitrary code execution or denial of service
Weaknesses CWE-825
References
Metrics threat_severity

None

threat_severity

Moderate

Type Values Removed Values Added
Title Use-After-Free in libexpat Due to Missing Handler Depth Tracking for Custom Encoding Callbacks
Type Values Removed Values Added
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.
First Time appeared Libexpat Project
Libexpat Project libexpat
Weaknesses CWE-416
CPEs cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*
Vendors & Products Libexpat Project
Libexpat Project libexpat
References
Metrics cvssV3_1

{'score': 4.9, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Nov 10, 2026, 12:49 PM
Reserved
Aug 20, 2026, 4:28 AM
Status
Modified
Published
Aug 20, 2026, 5:16 AM
Modified
Nov 10, 2026, 1:19 PM
Severity
Moderate
Public date
Aug 20, 2026, 4:28 AM