4.9

CVE-2025-2559: keycloak

CVSS: 4.9v3.1MediumDeferred
AliasesCGA-wq9m-pmfc-464rCGA-x2r3-784w-px55GHSA-2935-2wfm-hhpv
Published 25-03-2025Last modified 21-09-2026
Open JSON

Vulnerability summary

CVE-2025-2559 is a medium (CVSS 4.9) vulnerability in keycloak. EPSS estimates a 0.70% chance of exploitation in the next 30 days, higher than 52.4% of scored vulnerabilities.

Overall risk
20/100
0100
Low · default modelHow is this calculated?
CVSS score
4.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.70%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 25-03-2025
    PublishedVulnerability first disclosed.
  2. 21-09-2026
    Last modifiedVulnerability information updated.

Description

A flaw was found in Keycloak. When the configuration uses JWT tokens for authentication, the tokens are cached until expiration. If a client uses JWT tokens with an excessively long expiration time, for example, 24 or 48 hours, the cache can grow indefinitely, leading to an OutOfMemoryError. This issue could result in a denial of service condition, preventing legitimate users from accessing the system.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.70%

Chance of exploitation in the next 30 days

Percentile

52%

Versus all other CVEs

30-day change

+0.02 pp

From 0.68% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.70%

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

Chainguard1 product
  • keycloakAll versions (No fix recorded)
Org.keycloak1 product
  • keycloak-services≤ 26.1.4
Wolfi1 product
  • keycloakAll versions (No fix recorded)

3 vendors · 3 products

References

12 links
Show all 12 references