CVE-2026-18218: Keycloak-services: keycloak-services: client not-before revocation ignored when realm not-before is older but nonzero
Vulnerability summary
CVE-2026-18218 is a medium (CVSS 5.4) Missing Authorization vulnerability in redhat build_of_keycloak. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 20.2% of scored vulnerabilities.
Timeline
- 31-07-2026PublishedVulnerability first disclosed.
- 16-09-2026Last modifiedVulnerability information updated.
Description
A flaw was found in the TokenManager component of the Keycloak identity management service. When an administrator attempts to revoke tokens for a specific application (client) using a "not-before" policy, the revocation may be silently ignored if the overall security realm already has an older, non-zero revocation policy in place. This issue can allow previously issued tokens to remain valid for refreshing sessions and accessing user information even after an administrator has attempted to invalidate them. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
CVSS metrics
2 scores · 2 sources · 1 version- CVE.orgCNA4.2MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:NDiffers
EPSS trend
Probability
0.29%
Chance of exploitation in the next 30 days
Percentile
20%
Versus all other CVEs
30-day change
Increase +0.12 pp
From 0.17% on 22-09-2026
Known exploited
Compare KEV catalogsNot in the CISA KEV catalog.
Not in the ENISA CNW catalog.
Not in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Redhat1 product
1 vendor · 1 product