CVE-2026-2603
Medium
Elevated severity or exploit probability.
CVSS base
8.1
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
EPSS — probability of exploitation (30 days)
0.4%
36.4th percentile
CISA KEV
Not listed
Weakness / dates
CWE-306
Published 2026-03-18 · modified 2026-08-18
CVSS breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
| Attack Vector | N | Network |
| Attack Complexity | L | Low |
| Privileges Required | L | Low |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | H | High |
| Integrity | H | High |
| Availability | N | None |
Timeline
- 2026-03-18 — Published (NVD)
- 2026-08-18 — Last modified (NVD)
Description
A flaw was found in Keycloak. A remote attacker could bypass security controls by sending a valid SAML response from an external Identity Provider (IdP) to the Keycloak SAML endpoint for IdP-initiated broker logins. This allows the attacker to complete broker logins even when the SAML Identity Provider is disabled, leading to unauthorized authentication.
Affected
References
- https://access.redhat.com/errata/RHSA-2026:3925
- https://access.redhat.com/errata/RHSA-2026:3926
- https://access.redhat.com/errata/RHSA-2026:3947
- https://access.redhat.com/errata/RHSA-2026:3948
- https://access.redhat.com/security/cve/CVE-2026-2603
- exploit https://bugzilla.redhat.com/show_bug.cgi?id=2440300
- https://access.redhat.com/errata/RHSA-2026:3925
- https://access.redhat.com/errata/RHSA-2026:3926
- https://access.redhat.com/errata/RHSA-2026:3947
- https://access.redhat.com/errata/RHSA-2026:3948
- https://access.redhat.com/security/cve/CVE-2026-2603
- exploit https://bugzilla.redhat.com/show_bug.cgi?id=2440300
- exploit https://bugzilla.redhat.com/show_bug.cgi?id=2440300
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-2603.json