{"id":"CVE-2026-33557","aliases":["BIT-kafka-2026-33557","EUVD-2026-23846","GHSA-28jg-cgg7-j4wc","UBUNTU-CVE-2026-33557"],"status":"published","title":"Apache Kafka: Missing JWT token validation in OAUTHBEARER authentication","description":"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.","severity":{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"adp","from":"cve"},"epss":{"day":"2026-11-10","score":0.00897,"percentile":0.5989,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-1285","CWE-303"],"published":"2026-04-20T13:28:43Z","modified":"2026-10-28T02:30:27Z","fixes":[{"ecosystem":"Maven","package":"org.apache.kafka:kafka-clients","fixed_in":["4.1.2"],"sources":["ghsa","osv"]},{"ecosystem":"Bitnami","package":"kafka","fixed_in":["4.1.2"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"Maven","package":"org.apache.kafka:kafka-clients","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.1.0"},{"fixed":"4.1.2"}]}]},{"source":"osv","ecosystem":"Bitnami","package":"kafka","ranges":[{"type":"SEMVER","events":[{"introduced":"4.1.0"},{"fixed":"4.1.2"}]}]},{"source":"osv","ecosystem":"Maven","package":"org.apache.kafka:kafka-clients","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.1.0"},{"fixed":"4.1.2"}]}],"versions":["4.1.0","4.1.1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"kafka","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.2.0u2-0ubuntu3.1","2.2.0u2-0ubuntu3.2","2.2.2u1-0ubuntu1+esm2"]}],"products":[{"vendor":"apache","product":"kafka"},{"vendor":"apache software foundation","product":"apache kafka"},{"vendor":"red hat","product":"openshift serverless"},{"vendor":"red hat","product":"red hat build of apache camel 4 for quarkus 3"},{"vendor":"red hat","product":"red hat build of apache camel for spring boot 4"},{"vendor":"red hat","product":"red hat build of apicurio registry 2"},{"vendor":"red hat","product":"red hat build of apicurio registry 3"},{"vendor":"red hat","product":"red hat build of debezium 2"},{"vendor":"red hat","product":"red hat build of debezium 3"},{"vendor":"red hat","product":"red hat build of quarkus"},{"vendor":"red hat","product":"red hat data grid 8"},{"vendor":"red hat","product":"red hat enterprise linux 8"},{"vendor":"red hat","product":"red hat enterprise linux 9"},{"vendor":"red hat","product":"red hat fuse 7"},{"vendor":"red hat","product":"red hat jboss enterprise application platform 7"},{"vendor":"red hat","product":"red hat jboss enterprise application platform 8"},{"vendor":"red hat","product":"red hat jboss enterprise application platform expansion pack"},{"vendor":"red hat","product":"red hat process automation 7"},{"vendor":"red hat","product":"streams for apache kafka 2"},{"vendor":"red hat","product":"streams for apache kafka 3"}],"references":[{"url":"https://kafka.apache.org/cve-list","tags":["vendor-advisory","Vendor Advisory","advisory","web"]},{"url":"https://lists.apache.org/thread/v57o00hm6yszdpdnvqx2ss4561yh953h","tags":["mailing-list","Mitigation","Vendor Advisory","advisory","article","web"]},{"url":"http://www.openwall.com/lists/oss-security/2026/04/17/2","tags":["Mailing List","discussion","web"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-33557","tags":["vdb-entry","x_refsource_REDHAT","web","advisory"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2459739","tags":["issue-tracking","x_refsource_REDHAT","web","report"]},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33557.json","tags":["x_sadp-csaf-vex","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33557","tags":["web","advisory"]},{"url":"https://github.com/apache/kafka/commit/01d8e7db8d08dbd538892b409457ea6bfcc2a422","tags":["web"]},{"url":"https://github.com/advisories/GHSA-28jg-cgg7-j4wc"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33557.json","tags":["advisory"]},{"url":"https://github.com/apache/kafka","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2026-33557","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-33557","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-33557","title":"Apache Kafka: Missing JWT token validation in OAUTHBEARER authentication","description":"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.","status":"published","published":"2026-04-20T13:28:43.669Z","modified":"2026-07-15T01:06:14.162Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"adp"},{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L","level":"high","assessor":"adp"}],"cwes":["CWE-1285","CWE-303"],"updated_at":"2026-11-02T14:20:07.609948Z"}],"euvd":[{"id":"EUVD-2026-23846","description":"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.","status":"published","published":"2026-04-20T13:28:43Z","modified":"2026-07-15T01:06:14Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"updated_at":"2026-11-02T18:19:56.47701Z"}],"ghsa":[{"id":"GHSA-28jg-cgg7-j4wc","title":"Apache Kafka does not validate JWT tokens in its OAUTHBEARER authentication implementation","description":"A security vulnerability has been identified in Apache Kafka. By 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\nApache advises 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.","status":"published","published":"2026-04-20T15:31:52Z","modified":"2026-04-24T15:29:33Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"cwes":["CWE-1285"],"updated_at":"2026-11-02T14:39:56.453138Z"}],"nvd":[{"id":"CVE-2026-33557","description":"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.","status":"published","published":"2026-04-20T14:16:18.78Z","modified":"2026-10-26T22:10:00.163Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"secondary"},{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L","level":"high","assessor":"secondary"}],"cwes":["CWE-1285","CWE-303"],"updated_at":"2026-11-02T14:12:15.120927Z"}],"osv":[{"id":"CVE-2026-33557","title":"Apache Kafka: Missing JWT token validation in OAUTHBEARER authentication","description":"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.","status":"published","published":"2026-04-20T13:28:43.669Z","modified":"2026-10-28T02:30:27.270900661Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"cwes":["CWE-1285"],"updated_at":"2026-11-02T15:45:01.896044Z"},{"id":"GHSA-28jg-cgg7-j4wc","title":"Apache Kafka does not validate JWT tokens in its OAUTHBEARER authentication implementation","description":"A security vulnerability has been identified in Apache Kafka. By 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\nApache advises 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.","status":"published","published":"2026-04-20T15:31:52Z","modified":"2026-09-10T03:50:42.200581867Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"cwes":["CWE-1285"],"updated_at":"2026-11-02T15:46:33.956911Z"},{"id":"UBUNTU-CVE-2026-33557","description":"A possible security vulnerability has been identified in Apache Kafka. By 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. We 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.","status":"published","published":"2026-04-20T14:16:00Z","modified":"2026-06-30T18:17:55.695237312Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"},{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L","level":"high"}],"updated_at":"2026-11-02T16:56:16.036833Z"},{"id":"BIT-kafka-2026-33557","title":"Apache Kafka: Missing JWT token validation in OAUTHBEARER authentication","description":"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.","status":"published","published":"2026-04-22T08:40:40.515Z","modified":"2026-09-08T08:48:23.785156619Z","updated_at":"2026-11-02T15:28:31.782692Z"}]}}