CVE-2026-7571
Keycloak: keycloak: access token disclosure and implicit flow bypass via forged client data
- 7.1HighCVSS base score
- 0.41%Exploitation in 30 daysEPSS · top 64% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By redhat
- 19 days later
· 19 days later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| redhatCNA (assigner) | 3.1 | High7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N |
| NVDNVD · Analyzed | 3.1 | High7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.41% · top 64% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.1.
Affected products
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
All versions: unaffected
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavenorg.keycloak:keycloak-servicesGHSA-hq3p-w4xv-x7vp (opens in a new tab)
What to do
Workaround: To mitigate this issue, restrict network access to the Keycloak authentication endpoint to trusted clients and networks. Implement firewall rules to control inbound connections to the Keycloak service ports, thereby reducing the attack surface and limiting who can initiate authentication flows and potentially exploit the implicit flow bypass. If the Keycloak service is reloaded or restarted, ensure these network restrictions remain in effect.
References
References4
- RHSA-2026:19596 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- RHSA-2026:19597 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-7571 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2464263 (opens in a new tab)issue-trackingx_refsource_REDHAT
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-30888 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-hq3p-w4xv-x7vp (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-7571)Record last updated .