Out-of-bounds Read Affecting expat package, versions <2.8.4-1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.35% (29th percentile)

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  • Snyk IDSNYK-ECHOLATEST-EXPAT-19233407
  • published23 Aug 2026
  • disclosed20 Aug 2026

Introduced: 20 Aug 2026

CVE-2026-76641  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

Upgrade Echo:latest expat to version 2.8.4-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream expat package and not the expat package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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 Base Scores

version 3.1