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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Apache Software Foundation | Apache Kafka | 4.1.0 – ≤ 4.1.1 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 18.04 LTS | kafka | No fix yet | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | apache-nifi | 2.8.0-r7 | — |
| Wolfi rolling | debezium-3.5-connector-jdbc +5 | 3.5.0-r3 | — |
| Wolfi rolling | debezium-connector-ibmi-3.5 +2 | 3.5.1-r1 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Maven | org.apache.kafka:kafka-clients | >= 4.1.0, < 4.1.2 | 4.1.2 | GHSA-28jg-cgg7-j4wc |
Advisories 12
- WID-SEC-2026-2437 Oracle Communications: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 22, 2026
- WID-SEC-2026-2444 Oracle Fusion Middleware: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 7, 2026
- NCSC-2026-0312 Kwetsbaarheden verholpen in Oracle Financial Services NCSC-NL (Netherlands) · Aug 19, 2026
- WID-SEC-2026-2895 Oracle Financial Services Applications: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 18, 2026
- WID-SEC-2026-1166 Apache Kafka: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 13, 2026
- NCSC-2026-0258 Kwetsbaarheden verholpen in Oracle Financial Services NCSC-NL (Netherlands) · Jul 22, 2026
- NCSC-2026-0256 Kwetsbaarheden verholpen in Oracle Communications NCSC-NL (Netherlands) · Jul 22, 2026
- NCSC-2026-0254 Kwetsbaarheden verholpen in Oracle database producten NCSC-NL (Netherlands) · Jul 22, 2026
- WID-SEC-2026-2445 Oracle Financial Services Applications: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 21, 2026
- WID-SEC-2026-2436 Oracle Construction and Engineering: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 21, 2026
- WID-SEC-2026-2431 Oracle SQL Developer: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 21, 2026
- WID-SEC-2026-1723 Oracle Communications Unified Assurance: Mehrere Schwachstellen BSI CERT-Bund (WID) · May 28, 2026
References
- https://kafka.apache.org/cve-list vendor-advisory
- https://lists.apache.org/thread/v57o00hm6yszdpdnvqx2ss4561yh953h mailing-list