# CVE-2026-15943: Keycloak improper validation of OIDC secret masking in keycloak-services

Source: https://junglewise.ai/threats/cve-2026-15943-keycloak-improper-validation-of-oidc-secret-masking-in-keycloak  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-17. Updated: 2026-07-17  
License: CC BY 4.0 with a link back

CVE-2026-15943 · Severity: medium · CVSS 5.5 · Published 2026-07-17

A security flaw was found in Keycloak, an open-source identity and access management tool. The issue allows a delegated administrator to trick the system into sending sensitive credentials (client secrets) to a server they control. By modifying specific configuration settings while using a placeholder value for the secret, the administrator can capture the actual secret, potentially leading to unauthorized access to external identity providers.

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-2026-15943 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-15943 being exploited in the wild.

**How severe is CVE-2026-15943?** Medium severity, with a CVSS score of 5.5, published 17 July 2026.

**Which products and versions are affected?** Red Hat build of Keycloak All versions using keycloak-services.

**Is there a fix for CVE-2026-15943?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-15943 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-15943?** 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.

## Technical details

An improper validation vulnerability exists in the IdentityProviderResource.updateIdpFromRep() function of Keycloak. When a delegated administrator with 'manage-identity-providers' permissions updates an OIDC identity provider using the masked client secret sentinel value (ComponentRepresentation.SECRET_VALUE), Keycloak reuses the existing plaintext secret without verifying if other security-sensitive fields have changed. An attacker can exploit this by changing the 'tokenUrl' to a malicious endpoint; Keycloak will then transmit the real secret to the attacker-controlled server during subsequent authentication flows. This bypasses the intended security boundary of secret masking in the administrative API.

## Affected products

- Red Hat Red Hat Build of Keycloak All versions using keycloak-services

## Timeline

- 2026-07-16: disclosed: Initial report in Red Hat Bugzilla
- 2026-07-17: advisory: NVD publication date

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/jbossnetwork/restricted/listSoftware.html](https://access.redhat.com/jbossnetwork/restricted/listSoftware.html)
- [https://access.redhat.com/security/cve/CVE-2026-15943](https://access.redhat.com/security/cve/CVE-2026-15943)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2501270](https://bugzilla.redhat.com/show_bug.cgi?id=2501270)

## 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 OIDC Dynamic Client Registration offline token revocation bypass](https://junglewise.ai/threats/cve-2026-107623-a-flaw-was-found-in-the-oidc-dynamic-client-registration-dcr)