expat: Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption b...
CVE-2026-76641 is fixed in 4 products on 1 platform, first by expat 2.2.5-3ubuntu0.9+esm5, released August 20, 2026. It is not reported as exploited. Patch Radar priority: Routine.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| MozillaFirefox · opensuse-leap 16.0 | 153.5.0-160000.1.1 | OPENSUSE-SU-2026:22139-1 | Nov 7, 2026 |
| MozillaFirefox · sles 15.6 | 153.5.0-150400.157.16.1 | SUSE-SU-2026:4834-1 | Nov 7, 2026 |
| MozillaFirefox · sles 15.7 | 153.5.0-150400.157.16.1 | SUSE-SU-2026:4834-1 | Nov 7, 2026 |
| MozillaFirefox · sles 16.0 | 153.5.0-160000.1.1 | SUSE-SU-2026:24260-1 | Nov 7, 2026 |
| MozillaThunderbird · sles 15.7 | 153.5.0-150400.13.9.1 | SUSE-SU-2026:4736-1 | Nov 7, 2026 |
| expat · Ubuntu 18.04.6 LTS (bionic) | 2.2.5-3ubuntu0.9+esm5 | expat 2.2.5-3ubuntu0.9+esm5 | Aug 20, 2026 |
| expat · Ubuntu 20.04 LTS (focal) | 2.2.9-1ubuntu0.8+esm3 | expat 2.2.9-1ubuntu0.8+esm3 | Aug 20, 2026 |
| expat · Ubuntu 22.04.1 LTS (jammy) | 2.4.7-1ubuntu0.9 | expat 2.4.7-1ubuntu0.9 | Aug 20, 2026 |
| expat · Ubuntu 24.04.5 LTS (noble) | 2.6.1-2ubuntu0.6 | expat 2.6.1-2ubuntu0.6 | Aug 20, 2026 |
| expat · Ubuntu 26.04.1 LTS (resolute) | 2.7.4-1ubuntu0.2 | expat 2.7.4-1ubuntu0.2 | Aug 20, 2026 |
| expat · opensuse-leap 16.0 | 2.8.4-160000.1.1 | OPENSUSE-SU-2026:21945-1 | Sep 24, 2026 |
| expat · sles 15.6 | 2.8.5-150400.3.40.1 | SUSE-SU-2026:4623-1 | Nov 7, 2026 |
| expat · sles 15.7 | 2.8.5-150700.3.15.1 | SUSE-SU-2026:4619-1 | Nov 7, 2026 |
| expat · sles 16.0 | 2.8.4-160000.1.1 | SUSE-SU-2026:23912-1 | Sep 24, 2026 |
| libexpat1 · Ubuntu 18.04.6 LTS (bionic) | 2.2.5-3ubuntu0.9+esm5 | libexpat1 2.2.5-3ubuntu0.9+esm5 | Aug 20, 2026 |
| libexpat1 · Ubuntu 20.04 LTS (focal) | 2.2.9-1ubuntu0.8+esm3 | libexpat1 2.2.9-1ubuntu0.8+esm3 | Aug 20, 2026 |
| libexpat1 · Ubuntu 22.04.1 LTS (jammy) | 2.4.7-1ubuntu0.9 | libexpat1 2.4.7-1ubuntu0.9 | Aug 20, 2026 |
| libexpat1 · Ubuntu 24.04.5 LTS (noble) | 2.6.1-2ubuntu0.6 | libexpat1 2.6.1-2ubuntu0.6 | Aug 20, 2026 |
| libexpat1 · Ubuntu 26.04.1 LTS (resolute) | 2.7.4-1ubuntu0.2 | libexpat1 2.7.4-1ubuntu0.2 | Aug 20, 2026 |
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