UBUNTU-CVE-2026-33557

See a problem?
Please try reporting it to the source first.
Source
https://ubuntu.com/security/CVE-2026-33557
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33557.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-33557
Upstream
Published
2026-04-20T14:16:00Z
Modified
2026-06-30T18:17:23.069178459Z
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
  • 8.6 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L CVSS Calculator
  • Ubuntu - medium
Summary
[none]
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.

References

Affected packages

Ubuntu:Pro:18.04:LTS / kafka

Package

Name
kafka
Purl
pkg:deb/ubuntu/kafka?arch=source&distro=esm-apps%2Fbionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

2.*
2.2.0u2-0ubuntu3.1
2.2.0u2-0ubuntu3.2
2.2.2u1-0ubuntu1+esm2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.2.2u1-0ubuntu1+esm2",
            "binary_name": "kafka"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33557.json"