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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.

PUBLISHED Reserved 2026-05-20 | Published 2026-05-20 | Updated 2026-06-26 | Assigner redhat




MEDIUM: 6.4CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N

Problem types

Authorization Bypass Through User-Controlled Key

Product status

Default status
affected

26.4.13-1 (rpm) before *
unaffected

Default status
affected

26.4-19 (rpm) before *
unaffected

Default status
affected

26.4-19 (rpm) before *
unaffected

Default status
unaffected

Default status
affected

26.6.3-3 (rpm) before *
unaffected

Default status
affected

26.6-6 (rpm) before *
unaffected

Default status
affected

26.6-6 (rpm) before *
unaffected

Default status
unaffected

Timeline

2026-05-20:Reported to Red Hat.
2026-05-20:Made public.

References

access.redhat.com/errata/RHSA-2026:25097 (RHSA-2026:25097) vendor-advisory

access.redhat.com/errata/RHSA-2026:25098 (RHSA-2026:25098) vendor-advisory

access.redhat.com/errata/RHSA-2026:30049 (RHSA-2026:30049) vendor-advisory

access.redhat.com/errata/RHSA-2026:30050 (RHSA-2026:30050) vendor-advisory

access.redhat.com/security/cve/CVE-2026-9087 vdb-entry

bugzilla.redhat.com/show_bug.cgi?id=2480172 (RHBZ#2480172) issue-tracking

cve.org (CVE-2026-9087)

nvd.nist.gov (CVE-2026-9087)

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