Vulnerability in Apache Kafka
CVE-2026-33557
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…
EPSS: 0.006 (43.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
Affected products
- Apache Kafka
- Apache Software Foundation Kafka — versions 4.1.0
Weakness classification (CWE)
References
- security@apache.org (vendor-advisory, Vendor Advisory)
- security@apache.org (Vendor Advisory, mailing-list, Mitigation)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-33557?
- CVE-2026-33557 is a critical-severity vulnerability in Apache Kafka, classified under CWE-1285. CVSS score: 9.1/10. Published 2026-04-20.
- How severe is CVE-2026-33557?
- Critical severity. CVSS v3 base score is 9.1 out of 10.