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Fencer Vulns
high 8.1

CVE-2026-2603 json

Keycloak: keycloak: unauthorized authentication via disabled saml identity provider

published 2026-03-18 7 mo ago modified 2026-09-08 2 mo ago also BIT-keycloak-2026-2603 , EUVD-2026-12690 , GHSA-x4p7-7chp-64hq

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

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.

Patch / fix

  • maven org.keycloak:keycloak-services 26.5.5
  • maven org.keycloak:keycloak-server-spi-private 26.5.5
  • bitnami keycloak 26.2.14, 26.4.10
  • Red Hat Red Hat build of Keycloak 26.2 26.2-16, 26.2.14-1
  • Red Hat Red Hat build of Keycloak 26.4 26.4-12, 26.4.10-1

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-2026-2603 updated cvss 8.1

keycloak: Keycloak: Unauthorized authentication via disabled SAML Identity Provider

  • Red Hat build of Keycloak 26.2 rhbk/keycloak-rhel9 26.2-16, rhbk/keycloak-rhel9-operator 26.2-16, rhbk/keycloak-operator-bundle 26.2.14-1
    fixed: vendor fix RHSA-2026:3925
  • Red Hat build of Keycloak 26.2.14
    fixed: vendor fix RHSA-2026:3926
  • Red Hat build of Keycloak 26.4 rhbk/keycloak-rhel9 26.4-12, rhbk/keycloak-rhel9-operator 26.4-12, rhbk/keycloak-operator-bundle 26.4.10-1
    fixed: vendor fix RHSA-2026:3948
  • Red Hat build of Keycloak 26.4.10
    fixed: vendor fix RHSA-2026:3947

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
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
7 mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=2440300 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CISA ADP 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
OSV 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
maven org.keycloak:keycloak-services
<26.5.5
26.5.5
maven org.keycloak:keycloak-server-spi-private
<26.5.5
26.5.5
bitnami keycloak
>=26.2.0, <26.2.14
>=26.4.0, <26.4.10
26.2.14
26.4.10

Affected products

  • Red Hat Red Hat build of Keycloak 26.2
  • Red Hat Red Hat build of Keycloak 26.2.14
  • Red Hat Red Hat build of Keycloak 26.4
  • Red Hat Red Hat build of Keycloak 26.4.10

Classification

Weakness
  • CWE-306 Missing Authentication for Critical Functionality

References

Sources

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.