CVE-2026-56403

libexpat: libexpat: Arbitrary code execution due to integer overflow in storeAtts

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 storeAtts.

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 Integer Overflow in libexpat XML Parsing Library libexpat: libexpat: Arbitrary code execution due to integer overflow in storeAtts
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 libexpat XML Parsing Library
Type Values Removed Values Added
Description libexpat before 2.8.2 has an integer overflow in storeAtts.
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, 3:43 PM
Status
Modified
Published
Jun 21, 2026, 4:16 PM
Modified
Nov 10, 2026, 1:19 PM
Severity
Moderate
Public date
Jun 21, 2026, 3:43 PM