CVE-2026-25749
📋 TL;DR
A heap buffer overflow vulnerability in Vim's tag file resolution logic allows attackers to execute arbitrary code or crash the application by exploiting the 'helpfile' option. This affects all users running Vim versions prior to 9.1.2132. The vulnerability is triggered when processing help file tags with a specially crafted 'helpfile' value.
💻 Affected Systems
- Vim
📦 What is this software?
Vim by Vim
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, privilege escalation, or data exfiltration.
Likely Case
Application crash (denial of service) or limited code execution within Vim's context.
If Mitigated
No impact if patched or if the vulnerable functionality is not used.
🎯 Exploit Status
Exploitation requires user interaction (e.g., opening a malicious help file). No public exploits are known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 9.1.2132
Vendor Advisory: https://github.com/vim/vim/security/advisories/GHSA-5w93-4g67-mm43
Restart Required: No
Instructions:
1. Download Vim 9.1.2132 or later from https://github.com/vim/vim/releases/tag/v9.1.2132. 2. Compile and install following the platform-specific build instructions. 3. For package managers: Update using your system's package manager (e.g., apt upgrade vim, yum update vim).
🔧 Temporary Workarounds
Disable help file functionality
linuxPrevent Vim from loading help files by removing or restricting access to help directories.
chmod 000 /usr/share/vim/vim*/doc/
mv /usr/share/vim/vim*/doc/ /usr/share/vim/vim*/doc.bak/
Restrict helpfile option
allSet the helpfile option to a safe, controlled path in vimrc.
echo "set helpfile=/safe/path/to/help.txt" >> ~/.vimrc
🧯 If You Can't Patch
- Restrict user permissions to prevent execution of untrusted help files.
- Use application control to block Vim execution or limit it to trusted environments.
🔍 How to Verify
Check if Vulnerable:
Run 'vim --version' and check if version is below 9.1.2132.Check Version:
vim --version | head -1Verify Fix Applied:
Run 'vim --version' and confirm version is 9.1.2132 or higher.📡 Detection & Monitoring
Log Indicators:
- Vim crash logs
- System logs showing abnormal Vim process termination
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Process termination where process_name='vim' and exit_code != 0