High · CVSS 8.2CVE-2026-117610

libexpat through 2.9.0 NULL Pointer Dereference via External Entity SubparserCVE-2026-117610

Answer in brief

CVE-2026-117610 records a High severity (CVSS 8.2) vulnerability in libexpat through 2.9.0 NULL Pointer Dereference via External Entity Subparser. The current sources do not mark it as known exploited. The current feed maps libexpat/libexpat (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 28, 2026Updated Oct 28, 2026Source checked Oct 28, 2026First seen by HOL Oct 28, 2026Material review Oct 28, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.2
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 8.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps libexpat/libexpat (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
libexpat/libexpatgeneric	>=0 <=2.9.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for libexpat/libexpat.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Oct 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 28, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.

libexpat through 2.9.0 Integer Overflow in storeAtts via attIndex and nPrefixesSame libexpat/libexpat package