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CVE-2026-76641 Details

Description

Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XML_ExternalEntityParserCreate. A struct size mismatch between ELEMENT_TYPE members causes storeAtts to read the attIndex member past allocated memory boundaries, resulting in failure to normalize whitespace in non-CDATA attributes or a wild pointer dereference causing a segfault. This vulnerability was introduced by the fix for CVE-2026-66046.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:7.5 HIGHVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://github.com/libexpat/libexpat/commit/98599f6dcc2b460410881fe420f5f55d6bec63bf	[email protected]
https://github.com/libexpat/libexpat/pull/1331	[email protected]
https://www.vulncheck.com/advisories/expat-out-of-bounds-read-via-dtdcopy	[email protected]

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-125	Out-of-bounds Read	[email protected]

Affected Products

No affected product data is available for this CVE.

Change History

2 change records found show changes

Date	Action	Recorded By
Aug 20, 2026	CVE Modified	CISA-ADP
Aug 20, 2026	New CVE Received	[email protected]