CVE-2026-9087Keycloak: cross-session email verification proof not bound to upstream identity in first-broker-login
- 6.4MediumCVSS base score
- 0.31%Exploitation in 30 daysEPSS · top 76% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By redhat
Published
- 3 months later
· 3 months 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 | Medium6.4 | CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N |
| NVDNVD · Modified | 3.1 | High8.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N |
- EPSS (exploitation in 30 days)
- 0.31% · top 76% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.4.
Affected products
Red Hat · Red Hat build of Keycloak 26.4
- unaffected 26.4.13-1 – < *
Red Hat · Red Hat build of Keycloak 26.4
- unaffected 26.4-19 – < *
Red Hat · Red Hat build of Keycloak 26.4
- unaffected 26.4-19 – < *
Red Hat · Red Hat build of Keycloak 26.4.13
All versions: unaffected
Red Hat · Red Hat build of Keycloak 26.6
- unaffected 26.6.3-3 – < *
Red Hat · Red Hat build of Keycloak 26.6
- unaffected 26.6-6 – < *
Red Hat · Red Hat build of Keycloak 26.6
- unaffected 26.6-6 – < *
Red Hat · Red Hat build of Keycloak 26.6.3
All versions: unaffected
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavenorg.keycloak:keycloak-servicesGHSA-m6qj-3mpp-57v8 (opens in a new tab)
What to do
Workaround: To mitigate this issue, configure the affected identity provider to set `trustEmail=true`. This ensures that Keycloak trusts the email address provided by the upstream identity provider, bypassing the vulnerable verification flow. This mitigation should only be applied if the upstream identity provider is fully trusted to verify email addresses and prevent malicious account creation with existing email addresses. Configuration changes may require a Keycloak service restart or reload to take effect.
References
References6
- RHSA-2026:25097 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- RHSA-2026:25098 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- RHSA-2026:30049 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- RHSA-2026:30050 (opens in a new tab)vendor-advisoryx_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-9087 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2480172 (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-2026-31134 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-m6qj-3mpp-57v8 (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-2026-9087)Record last updated .