CVE-2026-9087 json
Keycloak: cross-session email verification proof not bound to upstream identity in first-broker-login
published 2026-05-20 5 mo ago modified 2026-08-03 3 mo ago also GHSA-m6qj-3mpp-57v8 , EUVD-2026-31134
- cvss
- 6.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 24%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- maven org.keycloak:keycloak-services 26.6.3
- Red Hat Red Hat build of Keycloak 26.4 26.4-19, 26.4.13-1
- Red Hat Red Hat build of Keycloak 26.6 26.6-6, 26.6.3-3
Vendor advisories
What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
red hat product security vex CVE-2026-9087 updated cvss 6.4
keycloak: Cross-Session Email Verification Proof Not Bound to Upstream Identity in First-Broker-Login
-
Red Hat build of Keycloak 26.4 rhbk/keycloak-rhel9 26.4-19, rhbk/keycloak-rhel9-operator 26.4-19, rhbk/keycloak-operator-bundle 26.4.13-1fixed: vendor fix RHSA-2026:30050
-
Red Hat build of Keycloak 26.4.13fixed: vendor fix RHSA-2026:30049
-
Red Hat build of Keycloak 26.6 rhbk/keycloak-rhel9 26.6-6, rhbk/keycloak-rhel9-operator 26.6-6, rhbk/keycloak-operator-bundle 26.6.3-3fixed: vendor fix RHSA-2026:25097
-
Red Hat build of Keycloak 26.6.3fixed: vendor fix RHSA-2026:25098
Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 5 mo ago
Exploit prediction
0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.4 | CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N |
| NVD | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N |
| GitHub | 3.1 | 6.4 | CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| maven | org.keycloak:keycloak-services | <26.6.3 |
26.6.3 |
Affected products
- 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
Classification
- Weakness
-
- CWE-639 Authorization Bypass Through User-Controlled Key
References
-
github.com
/keycloak/keycloak/commit/37dabf59d0b5ca3e5b3b272bcd3b2580e67b94dd
web
-
access.redhat.com
/errata/RHSA-2026:25097
vendor-advisory, web
-
access.redhat.com
/errata/RHSA-2026:25098
vendor-advisory, web
-
access.redhat.com
/errata/RHSA-2026:30049
vendor-advisory, web
-
access.redhat.com
/errata/RHSA-2026:30050
vendor-advisory, web
-
access.redhat.com
/security/cve/CVE-2026-9087
vdb-entry, web, vendor-advisory
-
bugzilla.redhat.com
/show_bug.cgi?id=2480172
issue-tracking, web, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-9087
advisory
-
github.com
/keycloak/keycloak
package
-
github.com
/keycloak/keycloak/releases/tag/26.6.3
web
Sources
- CVE List CVE-2026-9087
- GitHub Advisory GHSA-m6qj-3mpp-57v8
- NVD CVE-2026-9087
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.