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Keycloak logs sensitive headers

Moderate severity GitHub Reviewed Published Feb 10, 2026 to the GitHub Advisory Database • Updated Mar 4, 2026

Package

maven org.keycloak:keycloak-quarkus-server (Maven)

Affected versions

< 26.6.0

Patched versions

26.6.0

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.

References

Published by the National Vulnerability Database Feb 10, 2026
Published to the GitHub Advisory Database Feb 10, 2026
Reviewed Feb 11, 2026
Last updated Mar 4, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(0th percentile)

Weaknesses

Improper Output Neutralization for Logs

The product constructs a log message from external input, but it does not neutralize or incorrectly neutralizes special elements when the message is written to a log file. Learn more on MITRE.

CVE ID

CVE-2025-11537

GHSA ID

GHSA-gv3v-2cpp-3pmq

Source code

Credits

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