CVE-2024-53920

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-11-27 · updated 2026-09-21
Weakness: CWE-94

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.)

Affected products

GNU Emacs: before 30.1 — fixed in 30.1

How to fix

Upgrade to a fixed version: GNU Emacs 30.1. Check the vendor advisory for mitigations.

References

https://eshelyaron.com/posts/2024-11-27-emacs-aritrary-code-execution-and-how-to-avoid-it.html
https://git.savannah.gnu.org/cgit/emacs.git/tag/?h=emacs-30.0.92
https://git.savannah.gnu.org/cgit/emacs.git/tree/ChangeLog.4
https://git.savannah.gnu.org/cgit/emacs.git/tree/etc/NEWS?h=emacs-30.1
https://news.ycombinator.com/item?id=42256409
https://yhetil.org/emacs/CAFXAjY5f4YfHAtZur1RAqH34UbYU56_t6t2Er0YEh1Sb7-W=hg@mail.gmail.com/
http://www.openwall.com/lists/oss-security/2026/08/20/3
http://www.openwall.com/lists/oss-security/2026/08/20/7
http://www.openwall.com/lists/oss-security/2026/09/14/1
http://www.openwall.com/lists/oss-security/2026/09/21/9
https://lists.debian.org/debian-lts-announce/2025/02/msg00033.html

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