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CVE-2026-86143 Details

Description

In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling writecallback. This has security relevance for many types of uses of that length value within a callback.

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:7.3 HIGHVector:CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

CNA: [email protected]CVSS-B:6.9 MEDIUMVector:CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://github.com/GNOME/libxml2/commit/90f293ba74d28b1d570920382e707586f68ebf35	[email protected]	Patch
https://github.com/GNOME/libxml2/compare/v2.15.3...v2.15.4	[email protected]	Release Notes
https://gitlab.gnome.org/GNOME/libxml2/-/work_items/1111	[email protected]	ExploitVendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-192	Integer Coercion Error	[email protected]

Affected Products

Product	Versions
xmlsoft libxml2	< 2.15.4
CPE cpe:2.3:a:xmlsoft:libxml2:::::::: Remediation No remediation found in references.

Change History

3 change records found show changes

Date	Action	Recorded By
Sep 15, 2026	Initial Analysis	[email protected]
Sep 8, 2026	CVE Modified	CISA-ADP
Sep 5, 2026	New CVE Received	[email protected]