CVE-2026-11800
Org.keycloak:keycloak-services: keycloak: authentication bypass via jwt algorithm confusion
HIGH 8.1
En bref
- Source
- NVD
- EPSS
- EPSS 0.30 % · centile 23 ()
- État
- PUBLISHED
- Publiée
- Mise à jour
- Attribuée par
- redhat
- Statut NVD
- Analyzed
Description
A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to impersonate any federated user linked to the affected Identity Provider, leading to unauthorized access and potential privilege escalation.
Faiblesses (CWE)
- CWE-347 — Vérification incorrecte d'une signature cryptographique
Références
Scores
| Version | Score | Vecteur | Évalué par |
|---|---|---|---|
| CVSS 3.1 | HIGH 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N | redhat |
| CVSS 3.1 | HIGH 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N | redhat-SADP |
| CVSS 3.1 | HIGH 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N | NVD · secalert@redhat.com (Secondary) |
| CVSS 3.1 | HIGH 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
Références européennes
- ENISA EUVD · EUVD-2026-39567
- GCVE · GCVE-0-2026-11800
Avis du CERT-FR
- CERTFR-2026-AVI-0815 — Multiples vulnérabilités dans KeyCloak · cert.ssi.gouv.fr
Configurations affectées (CPE NVD)
cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*≥ 26.6 < 26.6.4
Produits affectés
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |