CVE-2023-39846
📋 TL;DR
This vulnerability allows attackers to bypass authentication in Konga v0.14.9 by crafting malicious JWT tokens. Attackers can gain unauthorized administrative access to the Konga management interface. Any organization running the vulnerable Konga version is affected.
💻 Affected Systems
- Konga
📦 What is this software?
Konga by Pantsel
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of Konga instance allowing attackers to reconfigure Kong API Gateway, intercept/modify traffic, deploy malicious plugins, and access sensitive API data.
Likely Case
Unauthorized administrative access to Konga dashboard leading to API gateway configuration changes, service disruption, and potential data exposure.
If Mitigated
Limited impact if Konga is isolated in internal network with strict firewall rules and Kong API Gateway has separate authentication.
🎯 Exploit Status
Public technical details available showing JWT manipulation technique. Exploitation requires minimal technical skill.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v0.14.10 or later
Vendor Advisory: https://github.com/pantsel/konga/releases
Restart Required: Yes
Instructions:
1. Backup current Konga configuration and data. 2. Stop Konga service. 3. Update to v0.14.10 or later via package manager or manual installation. 4. Restart Konga service. 5. Verify authentication is working.
🔧 Temporary Workarounds
Network Isolation
linuxRestrict Konga access to trusted IP addresses only
iptables -A INPUT -p tcp --dport 1337 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 1337 -j DROP
Reverse Proxy Authentication
allAdd additional authentication layer via reverse proxy
# Configure nginx with basic auth: location / { auth_basic 'Restricted'; auth_basic_user_file /etc/nginx/.htpasswd; proxy_pass http://localhost:1337; }
🧯 If You Can't Patch
- Immediately restrict Konga access to internal network only via firewall rules
- Implement network segmentation to isolate Konga from production Kong API Gateway
🔍 How to Verify
Check if Vulnerable:
Check Konga version via web interface or API endpoint. Version 0.14.9 is vulnerable.Check Version:
curl -s http://localhost:1337/api/status | grep versionVerify Fix Applied:
Attempt to authenticate with crafted JWT token; should be rejected. Verify Konga version is 0.14.10 or later.📡 Detection & Monitoring
Log Indicators:
- Failed authentication attempts with unusual JWT patterns
- Successful logins from unexpected IP addresses
- Configuration changes from unauthenticated users
Network Indicators:
- Unusual API calls to Konga endpoints without proper authentication headers
- Traffic to Konga port from unauthorized sources
SIEM Query:
source="konga.log" AND ("authentication failed" OR "jwt" OR "token") AND NOT user="authenticated_user"