---
id: CVE-2024-45491
title: An issue was discovered in libexpat before 2.6.3
summary: >-
  An issue was discovered in libexpat before 2.6.3. dtdCopy in xmlparse.c can
  have an integer overflow for nDefaultAtts on 32-bit platforms (where UINT_MAX
  equals SIZE_MAX).
severity: high
cvss: 7.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'
cvssSource: adp
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2024-08-30T13:53:48.624463Z'
published: '2024-08-30'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T00:50:06.088Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2024-45491'
references:
  - url: 'https://github.com/libexpat/libexpat/pull/891'
  - url: 'https://github.com/libexpat/libexpat/issues/888'
tags:
  - cve.org
epss: 0.0113
epssPercentile: 0.66228
ingestedAt: '2026-10-15T04:46:37.331Z'
---

## Overview

An issue was discovered in libexpat before 2.6.3. dtdCopy in xmlparse.c can have an integer overflow for nDefaultAtts on 32-bit platforms (where UINT_MAX equals SIZE_MAX).

## Remediation

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