Keycloak: keycloak: access token disclosure and implicit flow bypass via forged client data (Red Hat Red Hat build of Keycloak 26.4)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.41 % · percentile 36 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- redhat
- NVD status
- Analyzed
Description
A flaw was found in Keycloak. A low-privilege user, with knowledge of user credentials and client ID, can bypass a security control intended to disable the implicit flow in OpenID Connect (OIDC) clients. By manipulating client data during a session restart, an attacker can obtain an access token that should not be available. This vulnerability can also lead to the exposure of these access tokens in server logs, proxy logs, and HTTP Referrer headers, resulting in sensitive information disclosure.
Weaknesses (CWE)
- CWE-472 — External Control of Assumed-Immutable Web Parameter
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N | redhat |
| CVSS 3.1 | HIGH 7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N | NVD · secalert@redhat.com (Secondary) |
Advisories
- GHSA-hq3p-w4xv-x7vp — Keycloak: Access token disclosure and implicit flow bypass via forged client data
European references
- ENISA EUVD · EUVD-2026-30888
- GCVE · GCVE-0-2026-7571
Affected configurations (NVD CPE)
cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*≥ 26.4 < 26.4.12
Affected products
| Product | Versions |
|---|---|
| Red Hat · Red Hat build of Keycloak 26.4 | unaffected 26.4.12-1 < * |
| Red Hat · Red Hat build of Keycloak 26.4 | unaffected 26.4-17 < * |
| Red Hat · Red Hat build of Keycloak 26.4 | unaffected 26.4-17 < * |
| Red Hat · Red Hat build of Keycloak 26.4.12 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |