Vulnerability in libexpat

[ Description ]Official description

libexpat through 2.9.0 contains a NULL pointer dereference vulnerability in externalEntityInitProcessor2() in lib/xmlparse.c that mishandles the XML_TOK_NONE token from empty input. Attackers who control stream chunking can force an empty non-final first parse on an external entity subparser, causing a later parse to crash the application.

[ Fixes ]Fixes and patches

• Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
• Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
• Patch on vulncheck.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD

[ Advisories ]Government CERT advisories

• BSI CERT-Bund27 Oct 2026WID-SEC-2026-4214

  expat: Multiple vulnerabilities allow denial of service Translated from German

  CVE-2026-117610CVE-2026-118370

[ References ]References

• github.com/libexpat/libexpatProduct
• github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expat/lib/xm…Product
• github.com/libexpat/libexpat/commit/7b0d50e4b1d16fafd55876260701e04279a7489dPatch
• github.com/libexpat/libexpat/pull/1444Patch
• www.vulncheck.com/advisories/libexpat-through-2.9.0-null-pointer-dereference-via-extern…PatchVendor Advisory