Org.keycloak/keycloak-services: session fixation in oidc login flow that can lead to account takeover

{
  "id": "dfde686cb6472aab38e12b53317e33a8d84de235f74f2d4150aa0f97e7bfecd2",
  "url": "https://osv.dev/vulnerability/BIT-keycloak-2026-7507",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Org.keycloak/keycloak-services: session fixation in oidc login flow that can lead to account takeover",
    "summary": "A session fixation vulnerability was found in Keycloak's login-actions endpoints. An unauthenticated attacker could exploit this flaw by pre-creating an authentication session and tricking a victim into visiting a maliciously crafted link. By leveraging the /login-actions/restart endpoint—which processes session handles without adequate CSRF protection or cookie ownership validation—an attacker can reset the authentication flow state. This causes Single Sign-On (SSO) to authenticate the victim transparently upon clicking the link, allowing the attacker to hijack the required-action form without needing the victim's credentials. A successful exploit could lead to complete account takeover, including highly privileged administrative accounts.",
    "evidence": "osv:BIT-keycloak-2026-7507",
    "products": [
      {
        "name": {
          "value": "keycloak",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "26.4.12",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "BIT-keycloak-2026-7507",
      "aliases": [
        "BIT-keycloak-2026-7507",
        "CVE-2026-7507",
        "GHSA-hf67-5vvq-fm3r"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "26.4.0"
                },
                {
                  "fixed": "26.4.12"
                }
              ]
            }
          ],
          "package": {
            "name": "keycloak",
            "purl": "pkg:bitnami/keycloak",
            "ecosystem": "Bitnami"
          },
          "severity": [
            {
              "type": "CVSS_V3",
              "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"
            }
          ],
          "database_specific": {
            "source": "https://github.com/bitnami/vulndb/tree/main/data/keycloak/BIT-keycloak-2026-7507.json"
          }
        }
      ],
      "modified": "2026-10-07T14:30:05.108491672Z",
      "provider": "osv",
      "references": [
        "https://access.redhat.com/errata/RHSA-2026:19594",
        "https://access.redhat.com/errata/RHSA-2026:19595",
        "https://access.redhat.com/errata/RHSA-2026:19596",
        "https://access.redhat.com/errata/RHSA-2026:19597",
        "https://access.redhat.com/security/cve/CVE-2026-7507",
        "https://bugzilla.redhat.com/show_bug.cgi?id=2464145",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-7507",
        "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-7507.json",
        "https://access.redhat.com/errata/RHSA-2026:76132",
        "https://access.redhat.com/errata/RHSA-2026:76134",
        "https://access.redhat.com/errata/RHSA-2026:76128",
        "https://access.redhat.com/errata/RHSA-2026:76129",
        "https://access.redhat.com/errata/RHSA-2026:76130"
      ],
      "provider_metadata": {
        "cpes": [
          "cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*",
          "cpe:2.3:a:keycloak:keycloak:*:*:*:*:*:*:*:*"
        ],
        "severity": "High"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-7507",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 95091,
  "published_at": "2026-08-25T11:42:36.076+00:00"
}