CVE-2026-33557

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Source
https://cve.org/CVERecord?id=CVE-2026-33557
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33557.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-33557
Aliases
Downstream
Related
Published
2026-04-20T13:28:43.669Z
Modified
2026-07-16T03:30:52.420711812Z
Severity
  • 9.1 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
Summary
Apache Kafka: Missing JWT token validation in OAUTHBEARER authentication
Details

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.

Database specific 
{
    "cna_assigner": "apache",
    "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"
        }
    ],
    "cwe_ids": [
        "CWE-1285"
    ]
}
References

Affected packages

Git / github.com/apache/kafka

Affected ranges

Type
GIT
Repo
https://github.com/apache/kafka
Events
Introduced
13f70256db3c994c590e5d262a7cc50b9e973204
Fixed
c82fd9b934b4c1e6fa799e3f1dcc8f08d997740c
Database specific 
{
    "cpe": "cpe:2.3:a:apache:kafka:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "4.1.0"
        },
        {
            "fixed": "4.1.2"
        }
    ],
    "source": "CPE_RANGE"
}

Affected versions

4.*
4.1.0
4.1.0-rc3
4.1.1
4.1.1-rc1
4.1.1-rc2

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33557.json"