CVE-2026-18218Network attack vector

Token-revocation bypass via misordered not-before comparison

Published Jul 31, 2026 · Updated Jul 31, 2026

Token-revocation bypass in Red Hat build of Keycloak allows remote authenticated users to keep using client tokens after revocation. TokenManager.NotBeforeCheck prioritizes an older nonzero realm not-before timestamp over a newer client timestamp, so it fails to enforce the client policy. Exploitation requires that realm state and a valid OIDC token issued after the realm timestamp but before client revocation; refresh, introspection, and UserInfo requests remain accepted.

CVSS severity4.2
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Token-revocation bypass in Red Hat build of Keycloak allows remote authenticated users to keep using client tokens after revocation. TokenManager.NotBeforeCheck prioritizes an older nonzero realm not-before timestamp over a newer client timestamp, so it fails to enforce the client policy. Exploitation requires that realm state and a valid OIDC token issued after the realm timestamp but before client revocation; refresh, introspection, and UserInfo requests remain accepted.

The record

CVE
CVE-2026-18218
Published
Jul 31, 2026
Updated
Jul 31, 2026
Vendor
389 Directory Server
Product
Red Hat build of Keycloak
Classifications
CWE-862, T1550.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

389 Directory Server · Red Hat build of KeycloakAffected versions are unavailable in this record.

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
4.2Red HatCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
T1550.001Use Alternate Authentication Material: Application Access Token

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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