CVE-2026-118370libexpat through 2.9.0 Integer Overflow in storeAtts via attIndex and nPrefixes

Descripción

libexpat through 2.9.0 contains a signed integer overflow vulnerability in storeAtts() in lib/xmlparse.c that allows attackers to trigger out-of-bounds writes via oversized attribute counts. Attackers can supply a multi-gigabyte document with a start tag carrying over 2^30 attributes to overflow attIndex and nPrefixes, crashing applications or corrupting heap memory.

Datos: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Se publican tal como los indican las fuentes, en inglés.

Productos y versiones afectados

Referencias y parches

• https://github.com/libexpat/libexpat/pull/1450 patchissue-trackingPatch
• https://github.com/libexpat/libexpat/commit/1bac53c4fc460a03cd9860f39501c7979f6750ae patchPatch
• https://github.com/libexpat/libexpat/commit/621cb2c78b253ee023a86bc91d6ddb048481c04c patchPatch
• https://github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expat/lib/xmlparse.c#L4138-L4140 technical-descriptionProduct
• https://github.com/libexpat/libexpat productProduct
• VulnCheck Advisory: libexpat through 2.9.0 Integer Overflow in storeAtts via attIndex and nPrefixes third-party-advisoryPatchThird Party Advisory