CVE-2026-50219

expat: libexpat: Use-after-free vulnerability due to improper handler call depth tracking

Published Jun 4, 2026 CVSS 3.1 · 4.9 Medium EPSS < 1% KEV · Not listed
Description
libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_GetBuffer, XML_Parse, XML_ParseBuffer, XML_ParserFree, or XML_ParserReset from within handlers in cases of a policy violation. Thus, a use-after-free can occur,

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4765-1 expat security update
Debian DSA Debian DSA DSA-6404-1 expat security update
Ubuntu USN Ubuntu USN USN-8790-1 Expat vulnerabilities
History
Type Values Removed Values Added
Title Use‑After‑Free in libexpat XML Parser Due to Missing Call Depth Tracking expat: libexpat: Use-after-free vulnerability due to improper handler call depth tracking
Weaknesses CWE-911
References
Metrics threat_severity

None

threat_severity

Moderate

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 XML Parser Due to Missing Call Depth Tracking
Type Values Removed Values Added
Description libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_GetBuffer, XML_Parse, XML_ParseBuffer, XML_ParserFree, or XML_ParserReset from within handlers in cases of a policy violation. Thus, a use-after-free can occur,
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, 12:47 PM
Reserved
Jun 4, 2026, 4:20 AM
Status
Modified
Published
Jun 4, 2026, 6:16 AM
Modified
Nov 10, 2026, 1:19 PM
Severity
Moderate
Public date
Jun 4, 2026, 4:20 AM