Keycloak has an improper input validation vulnerability
A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints that operators believe are not externally reachable.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.keycloak:keycloak-quarkus-server | <= 26.2.5 | no fix |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N- Weakness (CWE)
CWE-20- Platform
- Java / Kotlin (Maven)
- Package
org.keycloak:keycloak-quarkus-server- Disclosed
- 15.01.2026
- Updated
- 11.10.2026 12:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-v897-pv23-r8cw - CC BY 4.0
Vulnerability history: org.keycloak:keycloak-quarkus-server
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 9
- First → latest
- 11.2024 02.2026
- Without a fix
- 1
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 6
- Low 2
Disclosures per year
- 2024: 3
- 2025: 4
- 2026: 2
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Keycloak has an improper input validation vulnerability this entry
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