{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:apache:kafka:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "4.1.0"
              },
              {
                "fixed": "4.1.2"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "13f70256db3c994c590e5d262a7cc50b9e973204"
            },
            {
              "fixed": "c82fd9b934b4c1e6fa799e3f1dcc8f08d997740c"
            }
          ],
          "repo": "https://github.com/apache/kafka",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "apache",
    "cwe_ids": [
      "CWE-1285"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33557.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "4.1.0"
          },
          {
            "last_affected": "4.1.1"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "A possible security vulnerability has been identified in Apache Kafka.\n\nBy default, the broker property `sasl.oauthbearer.jwt.validator.class` is set to `org.apache.kafka.common.security.oauthbearer.DefaultJwtValidator`. It accepts any JWT token without validating its signature, issuer, or audience. An attacker can generate a JWT token from any issuer with the `preferred_username` set to any user, and the broker will accept it.\n\nWe advise the Kafka users using kafka v4.1.0 or v4.1.1 to set the config `sasl.oauthbearer.jwt.validator.class` to `org.apache.kafka.common.security.oauthbearer.BrokerJwtValidator` explicitly to avoid this vulnerability. Since Kafka v4.1.2 and v4.2.0 and later, the issue is fixed and will correctly validate the JWT token.",
  "id": "CVE-2026-33557",
  "modified": "2026-07-16T03:30:52.420711812Z",
  "published": "2026-04-20T13:28:43.669Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/04/17/2"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33557.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/security/cve/CVE-2026-33557"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33557.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://kafka.apache.org/cve-list"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33557"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2459739"
    },
    {
      "type": "ARTICLE",
      "url": "https://lists.apache.org/thread/v57o00hm6yszdpdnvqx2ss4561yh953h"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Apache Kafka: Missing JWT token validation in OAUTHBEARER authentication"
}