High 7.5Published Aug 20, 2026

CVE-2026-76641Expat Out-of-Bounds Read via dtdCopy

Updated under an hour ago (2026-10-19 06:50 UTC)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for libexpat

Exploited in the last 30 days

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: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-125
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Awaiting Analysis
Record last updated: Oct 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

libexpat libexpat libexpat:libexpat (from the name)	through 2.8.3	CNA record

References

https://github.com/libexpat/libexpat/pull/1331issue-tracking
https://github.com/libexpat/libexpat/commit/98599f6dcc2b460410881fe420f5f55d6bec63bfpatch
https://www.vulncheck.com/advisories/expat-out-of-bounds-read-via-dtdcopythird-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.