CVE-2026-76641

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/libexpat/libexpat/commit/98599f6dcc2b460410881fe420f5f55d6bec63bf
https://github.com/libexpat/libexpat/pull/1331
https://www.vulncheck.com/advisories/expat-out-of-bounds-read-via-dtdcopy

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-20 18:16

Updated : 2026-08-20 19:17

NVD link : CVE-2026-76641

Mitre link : CVE-2026-76641

CVE.ORG link : CVE-2026-76641

JSON object : View

Products Affected

No product.

CWE

CWE-125

Out-of-bounds Read

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