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Keycloak lets PAR authorization requests be reused after flow restart

Priority LOW 24CWE-670Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

Red Hat Build of Keycloak's keycloak-services component mishandles Pushed Authorization Requests (PAR) when an authentication flow is restarted. The restart clears the internal markers that track PAR consumption while the request stays active, so the same authorization request can be reused. A remote attacker with low privileges can use this to obtain multiple access tokens, bypassing the single-use requirement. The flaw is classified as CWE-670.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

A flaw was found in the Pushed Authorization Request PAR implementation of the keycloak-services component. The issue occurs when an authentication flow is restarted, which incorrectly clears the internal markers used to track PAR consumption while leaving the request active. This allows an attacker to reuse the same authorization request to obtain multiple access tokens, bypassing security requirements for single-use requests.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00193 9th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

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——No fix listedCNA
Red HatRed Hat Build of Keycloak——No fix listedCNA
Red HatRed Hat Single Sign-On 7——Not affectedCNA
  • Red Hat Build of Keycloak VendorRed Hat Affected — Fixed in — No fix listed CNA
  • Red Hat Build of Keycloak VendorRed Hat Affected — Fixed in — No fix listed CNA
  • Red Hat Single Sign-On 7 VendorRed Hat Affected — Fixed in — Not affected CNA

CPE names CNA · 2

CPEVersionsRoleVendor
cpe:/a:redhat:build_keycloak:——Red Hat
cpe:/a:redhat:red_hat_single_sign_on:77—Red Hat
  • cpe:/a:redhat:build_keycloak: Versions — — ·Red Hat
  • cpe:/a:redhat:red_hat_single_sign_on:7 Versions 7 — ·Red Hat

Remediation

The sources list no fixed version for Red Hat Build of Keycloak. Red Hat Single Sign-On 7 is not affected.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Build of KeycloakAffectedNo fix yet
Not affected: 1 product
  • Red Hat Single Sign-On 7

Timeline

  1. 2026-10-29 Threatist record created from CVE-2026-117859
  2. 2026-10-29 Affected versions changed · Red Hat
  3. 2026-10-29 CVSS score added · Red Hat
  4. 2026-10-29 Alias added: GHSA-3cf5-cf36-hfwx
  5. 2026-10-29 CISA SSVC decision points changed
  6. 2026-10-29 Priority changed: MEDIUM → LOW

References

  • TI-2019-15875 Protection mechanism failure in Jenkins Pipeline: Groovy Plugin KEVCVSS 3.1CRITICAL 9.9
  • TI-2019-15874 Protection mechanism failure in Jenkins Script Security Plugin KEVCVSS 3.1CRITICAL 9.9
  • TI-2019-08259 Underflow in PHP-FPM can lead to RCE KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-05363 Code injection in Elastic Kibana KEVCVSS 3.1CRITICAL 10.0
  • TI-2019-03949 Out-of-bounds write in ESXi and Horizon DaaS KEVCVSS 3.1CRITICAL 9.8
  • TI-2018-16080 A code execution vulnerability exists in the Stapler web framework used by Jenkins 2.153… KEVCVSS 3.1CRITICAL 9.8
See all 7413 →

Sources