CVE-2026-76641
Public on 2026-08-20
Modified on 2026-08-22
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.
Severity
See what this means
CVSS v3 Base Score
See breakdown
Affected Packages
| Platform | Package | Release Date | Advisory | Status |
|---|---|---|---|---|
| Amazon Linux 2 - Core | expat | Not Affected | ||
| Amazon Linux 2023 | expat | Not Affected | ||
| Amazon Linux 2 - Firefox Extra | firefox | Not Affected | ||
| Amazon Linux 2023 | firefox | Not Affected | ||
| Amazon Linux 2 - Core | thunderbird | Not Affected | ||
| Amazon Linux 2023 | xmlrpc-c | Not Affected |
CVSS Scores
| Score Type | Score | Vector | |
|---|---|---|---|
| Amazon Linux | CVSSv3 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |