GHSA-P3V8-FM5P-V84H

Vulnerability from github – Published: 2026-05-28 06:31 – Updated: 2026-08-05 18:31
VLAI
Summary
Keycloak has an Improper Verification of Cryptographic Signature issue
Details

A flaw was found in Keycloak. When a JSON Web Encryption (JWE) encrypted request object is submitted, Keycloak may incorrectly process unsigned claims if the decrypted content is raw JSON, bypassing the configured signature policy. This allows a remote attacker to submit unauthorized claims, leading to a compromise of data integrity within the OpenID Connect (OIDC) authorization flow. While a redirect URI allowlist acts as a compensating control, this vulnerability violates OIDC Core and Financial-grade API (FAPI) signing requirements.

Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.keycloak:keycloak-services"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "26.6.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-9793"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-347"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-01T21:23:28Z",
    "nvd_published_at": "2026-05-28T05:16:40Z",
    "severity": "MODERATE"
  },
  "details": "A flaw was found in Keycloak. When a JSON Web Encryption (JWE) encrypted request object is submitted, Keycloak may incorrectly process unsigned claims if the decrypted content is raw JSON, bypassing the configured signature policy. This allows a remote attacker to submit unauthorized claims, leading to a compromise of data integrity within the OpenID Connect (OIDC) authorization flow. While a redirect URI allowlist acts as a compensating control, this vulnerability violates OIDC Core and Financial-grade API (FAPI) signing requirements.",
  "id": "GHSA-p3v8-fm5p-v84h",
  "modified": "2026-08-05T18:31:21Z",
  "published": "2026-05-28T06:31:09Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9793"
    },
    {
      "type": "WEB",
      "url": "https://github.com/keycloak/keycloak/issues/49429"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:50846"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:50847"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:50848"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:50849"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-9793"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2482460"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/keycloak/keycloak"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Keycloak has an Improper Verification of Cryptographic Signature issue"
}



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