libexpat 2.7.2 through 2.8.5 Integer Overflow in expat_realloc (CVE-2026-102633) | HOL Guard CVE

High · CVSS 8.2CVE-2026-102633

libexpat 2.7.2 through 2.8.5 Integer Overflow in expat_realloc

Answer in brief

CVE-2026-102633 records a High severity (CVSS 8.2) vulnerability in libexpat 2.7.2 through 2.8.5 Integer Overflow in expat_realloc. 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 Sep 29, 2026Updated Sep 29, 2026Source checked Sep 29, 2026First seen by HOL Sep 29, 2026Material review Sep 29, 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	>=2.7.2 <=2.8.5	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
Sep 29, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 29, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 29, 2026

Sources and claim methodology

Upstream source description

libexpat versions 2.7.2 through 2.8.5 contain an integer overflow vulnerability in expat_realloc() function on 32-bit platforms when computing allocation sizes. Attackers supplying malicious XML to applications parsing with vulnerable libexpat can cause heap buffer overflow, memory corruption, or denial of service.

Quoted source text, attributed separately from HOL analysis.