---
id: CVE-2022-22823
title: >-
  build_model in xmlparse.c in Expat (aka libexpat) before 2.4.3 has an integer
  overflow.
summary: >-
  build_model in xmlparse.c in Expat (aka libexpat) before 2.4.3 has an integer
  overflow.
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-190
  - CWE-190
vendor: libexpat_project
product: libexpat
affected:
  - libexpat < 2.4.3
  - nessus < 8.15.3
  - 'nessus >= 10.0.0, < 10.1.1'
  - debian_linux = 10.0
  - debian_linux = 11.0
  - sinema_remote_connect_server < 3.1
patched:
  - libexpat 2.4.3
  - nessus 10.1.1
  - sinema_remote_connect_server 3.1
published: '2022-01-10'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T16:17:25.613'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2022-22823'
references:
  - url: 'http://www.openwall.com/lists/oss-security/2022/01/17/3'
    label: cve@mitre.org
  - url: 'https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf'
    label: cve@mitre.org
  - url: 'https://github.com/libexpat/libexpat/pull/539'
    label: cve@mitre.org
  - url: 'https://security.gentoo.org/glsa/202209-24'
    label: cve@mitre.org
  - url: 'https://www.debian.org/security/2022/dsa-5073'
    label: cve@mitre.org
  - url: 'https://www.tenable.com/security/tns-2022-05'
    label: cve@mitre.org
  - url: 'http://www.openwall.com/lists/oss-security/2022/01/17/3'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/libexpat/libexpat/pull/539'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.gentoo.org/glsa/202209-24'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.debian.org/security/2022/dsa-5073'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.tenable.com/security/tns-2022-05'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-398330.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-484086.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
epss: 0.03404
epssPercentile: 0.88588
ingestedAt: '2026-10-14T16:40:32.042Z'
---

## Overview

build_model in xmlparse.c in Expat (aka libexpat) before 2.4.3 has an integer overflow.

## Affected

- `libexpat < 2.4.3`
- `nessus < 8.15.3`
- `nessus >= 10.0.0, < 10.1.1`
- `debian_linux = 10.0`
- `debian_linux = 11.0`
- `sinema_remote_connect_server < 3.1`

## Remediation

Upgrade past the affected range:

- `libexpat 2.4.3`
- `nessus 10.1.1`
- `sinema_remote_connect_server 3.1`