CVE-2025-61673
📋 TL;DR
CVE-2025-61673 is an authentication bypass vulnerability in Karapace versions 5.0.0 and 5.0.1 when configured with OAuth 2.0 Bearer Token authentication. An attacker can send requests without an Authorization header to bypass authentication entirely, gaining unauthorized read/write access to protected Schema Registry endpoints. Organizations using vulnerable Karapace versions with OAuth authentication are affected.
💻 Affected Systems
- Karapace
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of Schema Registry data including schema creation, modification, and deletion, potentially enabling data corruption, schema poisoning attacks, or facilitating downstream application attacks.
Likely Case
Unauthorized access to sensitive schema information, potential schema manipulation affecting data validation in Kafka applications, and exposure of internal data structures.
If Mitigated
Limited impact if proper network segmentation and additional authentication layers exist, but still represents a significant security control failure.
🎯 Exploit Status
Exploitation requires no authentication and minimal technical skill - simply omitting the Authorization header in requests to protected endpoints.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.0.2
Vendor Advisory: https://github.com/Aiven-Open/karapace/security/advisories/GHSA-vq25-vcrw-gj53
Restart Required: Yes
Instructions:
1. Backup current configuration and data. 2. Stop Karapace service. 3. Upgrade to version 5.0.2 using package manager or manual installation. 4. Restart Karapace service. 5. Verify authentication is working correctly.
🔧 Temporary Workarounds
Network Access Control
allRestrict network access to Karapace Schema Registry endpoints using firewall rules or network policies.
Switch Authentication Method
allTemporarily switch from OAuth 2.0 Bearer Token to Basic authentication or disable authentication if in a trusted environment.
Modify Karapace configuration to use 'authentication_type: basic' or 'authentication_type: none'
🧯 If You Can't Patch
- Implement strict network segmentation and firewall rules to limit access to Karapace endpoints
- Deploy a reverse proxy with additional authentication layer in front of Karapace
🔍 How to Verify
Check if Vulnerable:
Check Karapace version and authentication configuration. If version is 5.0.0 or 5.0.1 and OAuth 2.0 Bearer Token authentication is enabled, the system is vulnerable.Check Version:
karapace --version or check package manager (apt list --installed | grep karapace or rpm -qa | grep karapace)Verify Fix Applied:
After upgrading to 5.0.2, test authentication by sending requests without Authorization header to protected endpoints - they should return 401 Unauthorized.📡 Detection & Monitoring
Log Indicators:
- Successful requests to protected Schema Registry endpoints without authentication headers
- Unusual schema creation/modification patterns from unauthenticated sources
Network Indicators:
- HTTP requests to /subjects, /schemas, /compatibility, or /config endpoints without Authorization headers
SIEM Query:
source="karapace" AND (path="/subjects/*" OR path="/schemas/*" OR path="/compatibility/*" OR path="/config/*") AND NOT http.headers.authorization EXISTS