CVE-2026-56406

libexpat: libexpat: Arbitrary code execution via integer overflow in XML_ParseBuffer

Published Jun 21, 2026 CVSS 3.1 · 6.9 Medium EPSS < 1% KEV · Not listed
Description
libexpat before 2.8.2 has an integer overflow in XML_ParseBuffer because it lacked a check that was present in XML_Parse.

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
History
Type Values Removed Values Added
Title Integer Overflow in XML_ParseBuffer Causing Memory Corruption libexpat: libexpat: Arbitrary code execution via integer overflow in XML_ParseBuffer
References
Metrics threat_severity

None

threat_severity

Moderate

Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
Title Integer Overflow in XML_ParseBuffer Causing Memory Corruption
Type Values Removed Values Added
Description libexpat before 2.8.2 has an integer overflow in XML_ParseBuffer because it lacked a check that was present in XML_Parse.
First Time appeared Libexpat Project
Libexpat Project libexpat
Weaknesses CWE-190
CPEs cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*
Vendors & Products Libexpat Project
Libexpat Project libexpat
References
Metrics cvssV3_1

{'score': 6.9, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Nov 10, 2026, 12:48 PM
Reserved
Jun 21, 2026, 3:48 PM
Status
Modified
Published
Jun 21, 2026, 4:16 PM
Modified
Nov 10, 2026, 1:19 PM
Severity
Moderate
Public date
Jun 21, 2026, 3:48 PM