CVE-2021-26310
📋 TL;DR
This vulnerability in the TeamCity IntelliJ plugin allows denial-of-service attacks by crashing the plugin or IDE. It affects developers using IntelliJ IDEA with the TeamCity plugin installed. The vulnerability was present in versions before the fix.
💻 Affected Systems
- JetBrains IntelliJ IDEA TeamCity plugin
📦 What is this software?
Teamcity by Jetbrains
⚠️ Risk & Real-World Impact
Worst Case
Complete disruption of development workflow with IntelliJ IDEA crashing or becoming unresponsive, potentially causing data loss in unsaved work.
Likely Case
Temporary disruption of the TeamCity plugin functionality within IntelliJ IDEA, requiring restart of the IDE to restore normal operation.
If Mitigated
Minimal impact with proper plugin management and version control practices in place.
🎯 Exploit Status
Exploitation requires interaction with the TeamCity plugin within IntelliJ IDEA environment.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2020.2.2.85899 and later
Vendor Advisory: https://blog.jetbrains.com/blog/2021/05/07/jetbrains-security-bulletin-q1-2021/
Restart Required: Yes
Instructions:
1. Open IntelliJ IDEA. 2. Go to File → Settings → Plugins. 3. Find TeamCity plugin. 4. Click Update or install version 2020.2.2.85899+. 5. Restart IntelliJ IDEA.
🔧 Temporary Workarounds
Disable TeamCity plugin
allTemporarily disable the vulnerable plugin until patching is possible
Use alternative TeamCity integration
allUse TeamCity web interface or command line tools instead of the IntelliJ plugin
🧯 If You Can't Patch
- Restrict plugin usage to trusted TeamCity servers only
- Implement developer workstation isolation to limit blast radius
🔍 How to Verify
Check if Vulnerable:
Check plugin version in IntelliJ IDEA: File → Settings → Plugins → TeamCity → check version numberCheck Version:
No command line check - must be verified through IntelliJ IDEA GUIVerify Fix Applied:
Verify plugin version is 2020.2.2.85899 or higher in plugin settings📡 Detection & Monitoring
Log Indicators:
- IntelliJ IDEA crash logs
- TeamCity plugin error messages in IDE logs
Network Indicators:
- Unusual TeamCity server connection patterns from IDE
SIEM Query:
source="intellij_logs" AND ("TeamCity plugin crash" OR "plugin error")