CVE-2025-42921
📋 TL;DR
The JetBrains Toolbox App before version 2.6 had missing SSH host key verification in its SSH plugin, allowing potential man-in-the-middle attacks. This vulnerability affects users who connect to remote servers via SSH through the Toolbox App's SSH functionality. Attackers could intercept and manipulate SSH connections if they can position themselves between the user and the target server.
💻 Affected Systems
- JetBrains Toolbox App
📦 What is this software?
Toolbox by Jetbrains
⚠️ Risk & Real-World Impact
Worst Case
An attacker could perform a man-in-the-middle attack, intercepting SSH credentials, executing arbitrary commands on the remote server, or manipulating data in transit.
Likely Case
In targeted attacks, attackers could intercept SSH sessions in controlled network environments to steal credentials or access sensitive systems.
If Mitigated
With proper network segmentation and monitoring, the impact is limited to potential credential exposure in compromised network segments.
🎯 Exploit Status
Exploitation requires network access to intercept SSH connections and knowledge of SSH man-in-the-middle techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.6 and later
Vendor Advisory: https://www.jetbrains.com/privacy-security/issues-fixed/
Restart Required: Yes
Instructions:
1. Open JetBrains Toolbox App 2. Click on your profile icon 3. Select 'Check for Updates' 4. Install version 2.6 or later 5. Restart the Toolbox App
🔧 Temporary Workarounds
Disable SSH Plugin
allTemporarily disable the SSH plugin functionality until patching is possible
Use Native SSH Client
allUse your operating system's native SSH client instead of the Toolbox App SSH plugin
ssh user@hostname
🧯 If You Can't Patch
- Restrict network access to only trusted SSH servers and networks
- Implement network monitoring for unexpected SSH connection attempts
🔍 How to Verify
Check if Vulnerable:
Check Toolbox App version in Settings > About. If version is below 2.6 and you use SSH functionality, you are vulnerable.Check Version:
On Linux/macOS: 'jetbrains-toolbox --version' or check About in GUI. On Windows: Check About in GUI.Verify Fix Applied:
Verify version is 2.6 or higher in Settings > About, then test SSH connections to verify host key verification is working.📡 Detection & Monitoring
Log Indicators:
- Unexpected SSH connection failures
- SSH host key warnings in system logs
Network Indicators:
- Unusual SSH traffic patterns
- SSH connections to unexpected destinations
SIEM Query:
source="jetbrains-toolbox" AND (event="ssh_connection" OR event="ssh_error")