5

CVE-2025-11537: keycloak-26.4 Improper Output Neutralization for Logs

CVSS: 5.0v3.1MediumDeferred
AliasesCGA-6xr9-47rm-xh7rCGA-8g3w-8xg3-94mwCGA-9hr4-jxj3-3vfr
Published 10-02-2026Last modified 04-09-2026
Open JSON

Vulnerability summary

CVE-2025-11537 is a medium (CVSS 5.0) Improper Output Neutralization for Logs vulnerability in keycloak-26.4. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 5.2% of scored vulnerabilities.

Overall risk
20/100
0100
Low · default modelHow is this calculated?
CVSS score
5.0/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.16%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-X59G-8HJ7-JW6M

Timeline

  1. 10-02-2026
    PublishedVulnerability first disclosed.
  2. 04-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.16%

Chance of exploitation in the next 30 days

Percentile

5%

Versus all other CVEs

30-day change

+0.02 pp

From 0.15% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.16%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard12 products
  • keycloak-26.3-iamguarded-compatAll versions (No fix recorded)
  • keycloak-26.4All versions (No fix recorded)
  • keycloak-26.4-iamguarded-compatAll versions (No fix recorded)
  • keycloak-26.5< 26.5.6-r3
  • keycloak-26.5-iamguarded-compat< 26.5.6-r3
Wolfi4 products
  • keycloak-26.4All versions (No fix recorded)
  • keycloak-26.4-iamguarded-compatAll versions (No fix recorded)
  • keycloak-26.5< 26.5.6-r3
  • keycloak-26.5-iamguarded-compat< 26.5.6-r3
Org.keycloak1 product
  • keycloak-quarkus-server< 26.5.6

3 vendors · 17 products

References

8 links