CVE-2026-76641
Published: August 22, 2026Last modified: August 31, 2026
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 score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.5 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | expat | Fixed (2.8.3-r1) |
| 25 LTS | expat | Fixed (2.8.3-r1) | |
| Stream | expat | Fixed (2.8.3-r2) | |
| Hardened Containers | 23 LTS | expat | Unknown (2.5.0-r0) |
| 25 LTS | expat | Unknown (2.7.1-r0) | |
| Stream | expat | Unknown (2.4.9-r0) |