---
id: CVE-2026-102633
title: >-
  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
summary: >-
  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 li…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-190
vendor: libexpat
product: libexpat
affected:
  - libexpat >= 2.7.2 <= 2.8.5
published: '2026-09-29'
updated: '2026-09-29'
sourceUpdated: '2026-09-29T17:17:06.980'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-102633'
references:
  - url: 'https://github.com/libexpat/libexpat'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/libexpat/libexpat/blob/R_2_8_5/expat/lib/xmlparse.c#L1003
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/libexpat/libexpat/commit/209801d7fbaf07ab74bae8cb32dd2ab9e5846118
    label: disclosure@vulncheck.com
  - url: 'https://github.com/libexpat/libexpat/pull/1392'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/libexpat-2.7.2-through-2.8.5-integer-overflow-in-expat-realloc
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-29T16:52:16.830454Z'
ingestedAt: '2026-09-29T16:39:33.279Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.