CVE-2026-0976
📋 TL;DR
This vulnerability allows attackers to bypass reverse proxy path filtering by using RFC-compliant matrix parameters in URLs. Keycloak deployments behind common reverse proxy configurations are affected, potentially exposing administrative endpoints that operators believe are protected.
💻 Affected Systems
- Keycloak
⚠️ 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
Attackers gain unauthorized access to administrative interfaces or sensitive endpoints, leading to privilege escalation, data exposure, or system compromise.
Likely Case
Exposure of administrative interfaces that were intended to be internal-only, potentially enabling reconnaissance or limited unauthorized access.
If Mitigated
No impact if proper network segmentation and access controls are implemented beyond path filtering.
🎯 Exploit Status
Exploitation requires knowledge of internal endpoint paths and a vulnerable reverse proxy configuration.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Red Hat advisory for specific fixed versions
Vendor Advisory: https://access.redhat.com/security/cve/CVE-2026-0976
Restart Required: Yes
Instructions:
1. Review Red Hat advisory for patched versions. 2. Update Keycloak to the fixed version. 3. Restart Keycloak service. 4. Verify the fix.
🔧 Temporary Workarounds
Configure reverse proxy to handle matrix parameters
allUpdate reverse proxy configuration to properly parse and filter matrix parameters in URL paths
# Configuration depends on your reverse proxy (nginx, Apache, etc.)
Implement additional authentication layers
allAdd authentication requirements for all endpoints, not relying solely on path filtering
🧯 If You Can't Patch
- Implement network-level access controls (firewall rules) to restrict access to Keycloak administrative interfaces
- Deploy a WAF (Web Application Firewall) with rules to detect and block matrix parameter manipulation attempts
🔍 How to Verify
Check if Vulnerable:
Test if matrix parameters in URLs bypass your reverse proxy's path filtering rulesCheck Version:
keycloak --version or check Keycloak admin consoleVerify Fix Applied:
After patching, verify that matrix parameters no longer bypass path filtering📡 Detection & Monitoring
Log Indicators:
- Unusual requests containing semicolons (matrix parameters) in URL paths
- Access attempts to administrative endpoints from unexpected sources
Network Indicators:
- HTTP requests with matrix parameters (semicolon-separated) in path segments
SIEM Query:
http.url:*;* AND (http.url:*admin* OR http.url:*management*)