Security Update for Emacs: Mitigating Arbitrary Code Execution Vulnerability
Summary
ALSA-2025:4787: Moderate: emacs security update. Affects emacs versions < 1:27.2-11.el9_5.2. Fixed in 1:27.2-11.el9_5.2. How to fix ↓
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Background
GNU Emacs is a powerful, customizable, self-documenting text editor widely used for programming and text manipulation. It features advanced code editing capabilities, a built-in scripting language (elisp), and the ability to manage emails and news. However, a recent security vulnerability has been identified that could allow arbitrary code execution through Lisp macro expansion, posing a risk to users and their systems.
Vulnerability Detail
The vulnerability identified as CVE-2024-53920 allows for arbitrary code execution via Lisp macro expansion in Emacs. This issue arises from improper handling of user-defined macros, which can be exploited by an attacker to execute malicious code within the Emacs environment. The potential ramifications include unauthorized access to sensitive data, system compromise, and disruption of normal operations.
How To Fix
Minimum fixed version
1:27.2-11.el9_5.2
This is the first release that contains the fix.
sudo dnf update emacsTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary measure, users can disable the execution of untrusted Lisp code by configuring Emacs settings to restrict macro expansions. This can be done by adding the following line to your Emacs configuration file: '(setq byte-compile-warnings '(not free-vars unresolved)))'. However, this is not a permanent solution and updating is strongly recommended.
Conclusion
The identified vulnerability in Emacs poses a significant risk due to its potential for arbitrary code execution. Users are strongly encouraged to update to the latest patched version to ensure their systems remain secure. Temporary workarounds can mitigate risks but should not replace proper updates.
See every vulnerability recorded for emacs →
FAQ
CVE-2024-53920 is a security vulnerability in Emacs that allows arbitrary code execution through improper handling of Lisp macro expansions.
You can check if your version of Emacs is affected by visiting the Vulert playground at Vulert Scanner, where you can analyze your application's manifest file for vulnerabilities.
The risks include unauthorized code execution, potential data breaches, and system compromise, which can lead to significant security incidents.
Yes, a patch is available. Users should update to Emacs version 1:27.2-11.el9_5.2 to mitigate the vulnerability.
If you cannot update immediately, consider applying the temporary workaround by restricting macro expansions in your Emacs configuration.
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