CVE-2025-1244 Overview
A command injection vulnerability was discovered in the GNU Emacs text editor that could allow a remote, unauthenticated attacker to execute arbitrary shell commands on vulnerable systems. The vulnerability can be exploited by tricking users into visiting a specially crafted website or clicking an HTTP URL that contains a malicious redirect. This flaw represents a significant security risk as Emacs is widely deployed across Linux distributions and developer workstations.
Critical Impact
Remote attackers can achieve arbitrary shell command execution without authentication by luring users to malicious URLs or websites, potentially leading to complete system compromise.
Affected Products
- GNU Emacs (multiple versions)
- Red Hat Enterprise Linux distributions with Emacs packages
- Debian-based distributions with Emacs packages
Discovery Timeline
- February 12, 2025 - CVE-2025-1244 published to NVD
- November 3, 2025 - Last updated in NVD database
Technical Details for CVE-2025-1244
Vulnerability Analysis
This vulnerability falls under CWE-78 (Improper Neutralization of Special Elements used in an OS Command), commonly known as OS Command Injection. The flaw exists in how Emacs processes certain URL schemes or web content, where user-supplied input is passed to shell commands without proper sanitization.
When a user interacts with a maliciously crafted URL or visits a compromised website while using Emacs, the application fails to adequately validate or sanitize the input before passing it to system shell functions. This allows an attacker to inject arbitrary shell metacharacters and commands that are subsequently executed with the privileges of the Emacs process.
The attack requires user interaction—specifically, the victim must click on a malicious link or be redirected to a crafted URL. However, this is a relatively low bar for exploitation given the prevalence of phishing attacks and malicious redirects on the web.
Root Cause
The root cause of CVE-2025-1244 is insufficient input validation and sanitization when Emacs handles external URL schemes or HTTP redirects. The application fails to properly escape or neutralize shell metacharacters in URL parameters before executing system commands, allowing attackers to break out of the intended command context and inject malicious commands.
Attack Vector
The attack is network-based and requires user interaction. An attacker must craft a malicious URL containing shell command injection payloads and deliver it to the victim through various means:
- Phishing emails containing malicious links that, when clicked in an Emacs-based mail client or browser helper, trigger the vulnerability
- Compromised websites that automatically redirect users to crafted URLs
- HTTP redirect chains where a seemingly legitimate URL redirects to the malicious payload
Once the victim interacts with the malicious URL, Emacs processes the crafted input and executes the injected shell commands, potentially giving the attacker full control over the affected system.
The exploitation mechanism involves crafting URLs with embedded shell metacharacters that, when processed by Emacs' URL handling routines, are passed unsanitized to shell execution functions. Technical details are available in the Debian Bug Report #66390 and the Openwall OSS-Security Post.
Detection Methods for CVE-2025-1244
Indicators of Compromise
- Unexpected child processes spawned by Emacs processes (e.g., /bin/sh, /bin/bash, wget, curl, nc)
- Emacs process making unusual network connections to external hosts
- Shell command execution patterns in process logs originating from Emacs
- Suspicious URL patterns in web proxy or browser history logs containing shell metacharacters
Detection Strategies
- Monitor process creation events for shell processes spawned as children of Emacs
- Implement web filtering rules to block URLs containing suspicious shell metacharacter patterns
- Deploy endpoint detection rules for command injection patterns in URL handling
- Review Emacs configuration files for unexpected modifications indicating post-exploitation activity
Monitoring Recommendations
- Enable detailed process auditing on systems running Emacs to capture parent-child process relationships
- Configure SIEM rules to correlate Emacs process activity with outbound network connections
- Monitor for privilege escalation attempts following Emacs process execution
- Implement URL inspection at the network perimeter to detect exploitation attempts
How to Mitigate CVE-2025-1244
Immediate Actions Required
- Update Emacs to the latest patched version available from your distribution
- Apply security updates from Red Hat, Debian, or your respective Linux distribution immediately
- Restrict Emacs from handling external URLs if patching is not immediately possible
- Educate users about the risks of clicking untrusted links when using Emacs
Patch Information
Multiple Linux distributions have released security advisories and patches addressing this vulnerability:
- Red Hat: Multiple RHSA advisories are available including RHSA-2025:1915, RHSA-2025:1917, RHSA-2025:1961, RHSA-2025:1962, RHSA-2025:1963, RHSA-2025:1964, RHSA-2025:2022, RHSA-2025:2130, RHSA-2025:2157, RHSA-2025:2195, and RHSA-2025:2754
- Debian: See the Debian LTS Announcement February 2025
- GNU Emacs: Refer to the GNU Emacs News Update for upstream fix details
Workarounds
- Disable or restrict Emacs' ability to browse external URLs until patches are applied
- Configure email clients to use alternative applications for opening URLs
- Use network-level URL filtering to block potentially malicious redirect chains
- Consider running Emacs in a sandboxed environment with restricted shell access
# Update Emacs on Red Hat-based systems
sudo dnf update emacs
# Update Emacs on Debian-based systems
sudo apt update && sudo apt upgrade emacs
# Verify installed Emacs version
emacs --version
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
