CVE-2025-67124
📋 TL;DR
This vulnerability in miniserve allows attackers to overwrite arbitrary files outside the intended upload directory through a TOCTOU (Time-of-Check Time-of-Use) and symlink race condition. It affects deployments where uploads are enabled and attackers can create or replace filesystem entries in the upload destination directory. This is particularly dangerous in shared writable directory or volume scenarios.
💻 Affected Systems
- svenstaro/miniserve
📦 What is this software?
Miniserve by Svenstaro
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through overwriting critical system files, configuration files, or authorized_keys files, potentially leading to remote code execution or privilege escalation.
Likely Case
Data corruption, service disruption, or unauthorized file modification in the web server's context, potentially affecting other applications sharing the same filesystem.
If Mitigated
Limited impact if proper file permissions, isolation, and access controls prevent attackers from creating symlinks in the upload directory.
🎯 Exploit Status
Exploit requires precise timing (race condition) and ability to create symlinks in the upload directory. Public proof-of-concept exists in the GitHub gist reference.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.33.0 or later
Vendor Advisory: https://github.com/svenstaro/miniserve
Restart Required: Yes
Instructions:
1. Update miniserve to version 0.33.0 or later using cargo update miniserve. 2. Restart the miniserve service. 3. Verify the version with miniserve --version.
🔧 Temporary Workarounds
Disable upload functionality
allRemove upload capability entirely if not required
Do not use -u or --upload flags when starting miniserve
Restrict upload directory permissions
linuxPrevent symlink creation in upload directory
chmod 755 /path/to/upload/dir
chown root:root /path/to/upload/dir
🧯 If You Can't Patch
- Disable upload functionality completely if not required
- Run miniserve in a container with read-only filesystem for upload directory or use bind mounts with proper permissions
🔍 How to Verify
Check if Vulnerable:
Check if running miniserve version 0.32.0 or earlier with uploads enabledCheck Version:
miniserve --versionVerify Fix Applied:
Verify miniserve version is 0.33.0 or later and upload functionality still works as expected📡 Detection & Monitoring
Log Indicators:
- Multiple rapid file upload attempts with similar timestamps
- Failed file operations outside expected upload directory
Network Indicators:
- Unusual upload patterns with rapid successive requests
SIEM Query:
source="miniserve" AND (event="upload" OR event="file_write") AND (path NOT CONTAINS "/expected/upload/dir/")