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CVE-2026-117610

NULL pointer dereference in libexpat through 2.9.0

CVSS 4.0
8.2 high
EPSS
—
Published
·
Modified
Analyze CVE-2026-117610 with Vani AIImpact, affected versions, exploitation status, mitigations and detection

libexpat through 2.9.0 has a NULL pointer dereference in externalEntityInitProcessor2() in lib/xmlparse.c. It mishandles the XML_TOK_NONE token from empty input. A remote attacker who controls stream chunking can force an empty non-final first parse on an external-entity subparser so a later parse crashes the application. Applications that parse such XML with these libexpat versions are affected.

What to do: No fixed version is listed. Avoid attacker-controlled chunked XML that starts an external-entity subparser with an empty non-final buffer until libexpat is updated.

ProductAffected
libexpatthrough 2.9.0
Estimated exposure
No basis for an estimate.

Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.

Description · NVD

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.

Vendors
libexpat project
Products
libexpat
Weakness
CWE-476
Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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