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TI-2026-28102 Aliases CVE-2026-37977GHSA-5v8v-xvjv-57x7

Origin validation error in Red Hat build of Keycloak 26.4

Priority LOW 24CWE-346Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
Low · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-346.

Summary

A flaw was found in Keycloak. A remote attacker can exploit a Cross-Origin Resource Sharing (CORS) header injection vulnerability in Keycloak's User-Managed Access (UMA) token endpoint. This flaw occurs because the `azp` claim from a client-supplied JSON Web Token (JWT) is used to set the `Access-Control-Allow-Origin` header before the JWT signature is validated. When a specially crafted JWT with an attacker-controlled `azp` value is processed, this value is reflected as the CORS origin, even if the grant is later rejected. This can lead to the exposure of low-sensitivity information from authorization server error responses, weakening origin isolation, but only when a target client is misconfigured with `webOrigins: ["*"]`.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00258 17th percentileScored 2026-11-07
Fix Fixed org.keycloak:keycloak-services (Maven): 26.4.13, 26.6.3Red Hat: 4 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Red HatRed Hat build of Keycloak 26.4—26.4.13-1Patch availableCNA
Red HatRed Hat build of Keycloak 26.4—26.4-19Patch availableCNA
Red HatRed Hat build of Keycloak 26.4—26.4-19Patch availableCNA
Red HatRed Hat build of Keycloak 26.4.13——Not affectedCNA
Red HatRed Hat build of Keycloak 26.6—26.6.3-3Patch availableCNA
Red HatRed Hat build of Keycloak 26.6—26.6-6Patch availableCNA
Red HatRed Hat build of Keycloak 26.6—26.6-6Patch availableCNA
Red HatRed Hat build of Keycloak 26.6.3——Not affectedCNA
—org.keycloak:keycloak-services (Maven)before 26.4.1326.4.13Patch availableGHSA-5v8v-xvjv-57x7
—org.keycloak:keycloak-services (Maven)26.5.0 to before 26.6.326.6.3Patch availableGHSA-5v8v-xvjv-57x7
  • Red Hat build of Keycloak 26.4 VendorRed Hat Affected — Fixed in 26.4.13-1 Patch available CNA
  • Red Hat build of Keycloak 26.4 VendorRed Hat Affected — Fixed in 26.4-19 Patch available CNA
  • Red Hat build of Keycloak 26.4 VendorRed Hat Affected — Fixed in 26.4-19 Patch available CNA
  • Red Hat build of Keycloak 26.4.13 VendorRed Hat Affected — Fixed in — Not affected CNA
  • Red Hat build of Keycloak 26.6 VendorRed Hat Affected — Fixed in 26.6.3-3 Patch available CNA
  • Red Hat build of Keycloak 26.6 VendorRed Hat Affected — Fixed in 26.6-6 Patch available CNA
  • Red Hat build of Keycloak 26.6 VendorRed Hat Affected — Fixed in 26.6-6 Patch available CNA
  • Red Hat build of Keycloak 26.6.3 VendorRed Hat Affected — Fixed in — Not affected CNA
  • org.keycloak:keycloak-services (Maven) Vendor— Affected before 26.4.13 Fixed in 26.4.13 Patch available GHSA-5v8v-xvjv-57x7
  • org.keycloak:keycloak-services (Maven) Vendor— Affected 26.5.0 to before 26.6.3 Fixed in 26.6.3 Patch available GHSA-5v8v-xvjv-57x7

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:-:*:*:*not specified by NVDVulnerableRed Hat
  • cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:-:*:*:* Versions not specified by NVD Vulnerable ·Red Hat

Remediation

  • Fix · GHSA-5v8v-xvjv-57x7 org.keycloak:keycloak-services (Maven) Fixed in 26.4.13 Advisory →
  • Fix · GHSA-5v8v-xvjv-57x7 org.keycloak:keycloak-services (Maven) Fixed in 26.6.3 Advisory →

Red Hat 4 advisories

  • RHSA-2026:30050 Released 2026-06-25 · Red Hat rating Important
    Red Hat build of Keycloak 26.4.13 Images Security Update
    • Red Hat build of Keycloak 26.4 rhbk/keycloak-operator-bundle, rhbk/keycloak-rhel9, rhbk/keycloak-rhel9-operator
  • RHSA-2026:30049 Released 2026-06-25 · Red Hat rating Important
    Red Hat build of Keycloak 26.4.13 Security Update
    • Red Hat build of Keycloak 26.4.13
  • RHSA-2026:25098 Released 2026-06-10 · Red Hat rating Moderate
    Red Hat build of Keycloak 26.6.3 Update
    • Red Hat build of Keycloak 26.6.3
Show 1 more Red Hat advisories
  • RHSA-2026:25097 Released 2026-06-10 · Red Hat rating Moderate
    Red Hat build of Keycloak 26.6.3 Images Update
    • Red Hat build of Keycloak 26.6 rhbk/keycloak-operator-bundle, rhbk/keycloak-rhel9, rhbk/keycloak-rhel9-operator

Vendor assessments

Red Hat

Red Hat rating: Low. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat build of Keycloak 26.4Fixed RHSA-2026:30050
Red Hat build of Keycloak 26.4.13Fixed RHSA-2026:30049
Red Hat build of Keycloak 26.6Fixed RHSA-2026:25097
Red Hat build of Keycloak 26.6.3Fixed RHSA-2026:25098

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-37977
  2. 2026-10-03 Alias added: GHSA-5v8v-xvjv-57x7

References

Advisory 7

Other 6

  • TI-2026-02223 Keycloak: keycloak: unauthorized authentication via disabled saml identity provider CVSS 3.1HIGH 8.1
  • TI-2024-01049 Keycloak: path transversal in redirection validation CVSS 3.1HIGH 8.1
  • TI-2026-13740 Keycloak-services: keycloak-services: saml idp-initiated broker login bypasses link-only restriction CVSS 3.1CRITICAL 9.8
  • TI-2026-13741 Keycloak-services: keycloak-services: saml broker metadata import disables response signature validation CVSS 3.1CRITICAL 9.1
  • TI-2026-13106 Keycloak-services: keycloak-services: dcr protocol mapper type-swap policy bypass allows privilege escalation CVSS 3.1HIGH 8.8
  • TI-2026-02631 Authentication bypass in Red Hat build of Keycloak 26.2 CVSS 3.1HIGH 8.8
See all 110 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences