CVE-2026-76641 (GCVE-0-2026-76641)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:31 – Updated: 2026-10-01 15:21 X_Open Source
VLAI
Title
Expat Out-of-Bounds Read via dtdCopy
Summary
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.
Severity
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-20 18:48 UTC
CWE
Assigner
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 7141 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
libexpat libexpat Affected: 0 , ≤ 2.8.3 (semver)
    cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*
Create a notification for this product.
Date Public
2026-08-19 00:00
Credits
ZeyouLiu (@liuzeyouzeyou) ZeyouLiu (@liuzeyouzeyou)
Show details on NVD website
To clipboard 

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