CVE-2026-16442
HIGH 7.4A flaw was found in the SAML broker component of Keycloak, which is used to manage identity federation and user authentication. The issue occurs because the IdP-initiated Single Sign-On endpoint fails to check if a provider is restricted to account linking only. This allows an attacker with control over a linked upstream identity to bypass login restrictions and gain full access to a local user account.
Severe if exploited (CVSS 7.4), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.2%chance of exploitation in 30 days · 10th percentile
Impact if exploited
7.4CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityNone
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ⚠Complexity: Needs a race window or specific setup
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-16442/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-16442/poc.json
Affected
Products Red Hat Build Of Keycloak 26.4 Red Hat Build Of Keycloak 26.4.14 Red Hat Build Of Keycloak 26.6 Red Hat Build Of Keycloak 26.6.5 Red Hat Data Grid 8 Red Hat Jboss Enterprise Application Platform Expansion Pack Red Hat Single Sign On 7 Build Of Keycloak
Weakness (CWE)
- CWE-346: Origin Validation Error
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Redhat | Build Of Keycloak | ≥ 26.4 and < 26.4.14 |
| Redhat | Build Of Keycloak | ≥ 26.6 and < 26.6.5 |
All CVSS metrics
- HIGH 7.4 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - HIGH 7.4 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - CRITICAL 9.8 v3.1 · NVD Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
Advisories
- https://access.redhat.com/errata/RHSA-2026:50846
- https://access.redhat.com/errata/RHSA-2026:50847
- https://access.redhat.com/errata/RHSA-2026:50848
- https://access.redhat.com/errata/RHSA-2026:50849
- https://access.redhat.com/security/cve/CVE-2026-16442
- https://bugzilla.redhat.com/show_bug.cgi?id=2503138