# CVE-2026-107623: Keycloak OIDC Dynamic Client Registration offline token revocation bypass

Source: https://junglewise.ai/threats/cve-2026-107623-a-flaw-was-found-in-the-oidc-dynamic-client-registration-dcr  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-08. Updated: 2026-11-06  
License: CC BY 4.0 with a link back

CVE-2026-107623 · Severity: medium · CVSS 4.3 · Published 2026-10-08

Keycloak is an open-source identity and access management system that handles single sign-on for web and mobile applications. A bug in the OIDC Dynamic Client Registration component causes the backchannel logout offline token revocation setting to be silently disabled during client updates, allowing offline tokens to remain valid after a user's session is terminated. This could allow a user with a revoked offline token to continue accessing protected resources.

Technologies: [Red Hat build of Keycloak](https://junglewise.ai/threats/technologies/red-hat-keycloak). Vendors: [Red Hat](https://junglewise.ai/threats/vendors/red-hat).

## Quick answers

**Is CVE-2026-107623 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-107623 being exploited in the wild.

**How severe is CVE-2026-107623?** Medium severity, with a CVSS score of 4.3, published 8 October 2026.

**Which products and versions are affected?** Red Hat build of Keycloak before 26.6.8.

**Is there a fix for CVE-2026-107623?** Yes: fixed in Red Hat build of Keycloak 26.6.8. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-107623 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-107623?** Check whether you run Red Hat build of Keycloak at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in Red Hat build of Keycloak 26.6.8

## Technical details

The OIDC Dynamic Client Registration (DCR) endpoint has a response serialization bug that omits the backchannel logout offline token revocation setting when returning client configuration. When a client performs a standard update operation, this missing information causes the setting to be silently disabled, leaving offline tokens valid even after backchannel logout. No authentication is required to register a dynamic client; the vulnerability requires client-side action to trigger the configuration update.

## Affected products

- Red Hat build of Keycloak before 26.6.8

## Timeline

- 2026-10-08: disclosed
- 2026-11-06: advisory

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/errata/RHSA-2026:95761](https://access.redhat.com/errata/RHSA-2026:95761)

## Related threats

- [Keycloak server arbitrary code execution in client authorization](https://junglewise.ai/threats/cve-2026-120984-a-flaw-was-found-in-the-keycloak-server-s-client-management)
- [Red Hat Build of Keycloak OIDC logout session fixation](https://junglewise.ai/threats/cve-2026-107124-a-flaw-was-found-in-the-oidc-logout-endpoint-of-the-keycloak)
- [Keycloak theme resource disk exhaustion](https://junglewise.ai/threats/cve-2026-110932-a-flaw-was-found-in-the-theme-resource-endpoint-of-keycloak-an)
- [Keycloak secure-redirect-uris-enforcer open redirect via DNS resolution](https://junglewise.ai/threats/cve-2026-118425-a-flaw-was-found-in-the-secure-redirect-uris-enforcer-client)
- [Keycloak mTLS holder-of-key binding bypass in Standard Token Exchange](https://junglewise.ai/threats/cve-2026-97846-keycloak-provides-a-feature-called-mtls-holder-of-key-binding)