Description
A flaw was found in Keycloak. The cross-session verification proof is keyed only by (local userId,
idpAlias) and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim's local account.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat build of Keycloak 26.4 | — | — |
| Red Hat | Red Hat build of Keycloak 26.4.13 | — | — |
| Red Hat | Red Hat build of Keycloak 26.6 | — | — |
| Red Hat | Red Hat build of Keycloak 26.6.3 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | keycloak-26.5 +2 | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Maven | org.keycloak:keycloak-services | < 26.6.3 | 26.6.3 | GHSA-m6qj-3mpp-57v8 |
Advisories 1
- WID-SEC-2026-1616 Keycloak: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Jun 25, 2026
References
- RHSA-2026:25097 vendor-advisory
- RHSA-2026:25098 vendor-advisory
- RHSA-2026:30049 vendor-advisory
- RHSA-2026:30050 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-9087 vdb-entry
- RHBZ#2480172 issue-tracking