CVE-2025-11537 Keycloak-services: sensitive headers shown in the http access logs
Attackers with log access can steal credentials from verbose logs, enabling user impersonation and account takeover in Keycloak.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-11537?
CVE-2025-11537 is a medium-severity vulnerability in Red Hat Build of Keycloak, published on 10 Feb 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
A flaw was found in Keycloak. When the logging format is configured to a verbose, user-supplied pattern (such as the pre-defined 'long' pattern), sensitive headers including Authorization and Cookie are disclosed to the logs in cleartext. An attacker with read access to the log files can extract these credentials (e.g., bearer tokens, session cookies) and use them to impersonate users, leading to a full account compromise.
Weakness: CWE-117
Which versions are affected by CVE-2025-11537?
2 open source packages ship an affected version, including org.keycloak:keycloak-quarkus-server.
| Package | Affected | Fixed in |
|---|---|---|
org.keycloak:keycloak-quarkus-server Maven | All versions | 26.5.6 |
org.keycloak:keycloak-quarkus-server Maven | All versions | 26.5.6 |
How do I fix CVE-2025-11537?
Upgrade org.keycloak:keycloak-quarkus-server to 26.5.6 or later.
Is CVE-2025-11537 being exploited?
There is no known exploitation of CVE-2025-11537 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-YQ74765, ECHO-1ec0-58d1-cb3d, GHSA-gv3v-2cpp-3pmq, MINI-95x4-3vvw-4fwq, MINI-rmrj-h6q6-37x8.