CVE-2026-37977
Keycloak vulnerable to information disclosure via CORS header injection due to unvalidated JWT azp claim
描述
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: ["*"]`.
如何修補 CVE-2026-37977
要修補 CVE-2026-37977,請將受影響套件升級到下列已修補版本。
- —升級至 26.4.13 或更新版本
CVE-2026-37977 正在被利用嗎?
低 — EPSS 為 0.3%,目前沒有觀察到大規模利用活動。
受影響套件(1)
- from 0, < 26.4.13
CVSS 分數
| 來源 | 版本 | 嚴重程度 | 向量 |
|---|---|---|---|
| osv | CVSS 3.1 | LOW3.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N |