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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
org.apache.kafka:kafka-clientsMaven | >= 4.1.0, < 4.1.2 | 4.1.2 |
Affected products
23- osv-coords22 versionspkg:apk/chainguard/apache-nifipkg:apk/chainguard/debezium-3.5-connector-jdbcpkg:apk/chainguard/debezium-3.5-connector-mariadbpkg:apk/chainguard/debezium-3.5-connector-mongodbpkg:apk/chainguard/debezium-3.5-connector-mysqlpkg:apk/chainguard/debezium-3.5-connector-postgrespkg:apk/chainguard/debezium-3.5-connector-sqlserverpkg:apk/chainguard/debezium-connector-ibmi-3.5pkg:apk/chainguard/debezium-connector-informix-3.5pkg:apk/chainguard/debezium-connector-spanner-3.5pkg:apk/wolfi/apache-nifipkg:apk/wolfi/debezium-3.5-connector-jdbcpkg:apk/wolfi/debezium-3.5-connector-mariadbpkg:apk/wolfi/debezium-3.5-connector-mongodbpkg:apk/wolfi/debezium-3.5-connector-mysqlpkg:apk/wolfi/debezium-3.5-connector-postgrespkg:apk/wolfi/debezium-3.5-connector-sqlserverpkg:apk/wolfi/debezium-connector-ibmi-3.5pkg:apk/wolfi/debezium-connector-informix-3.5pkg:apk/wolfi/debezium-connector-spanner-3.5pkg:bitnami/kafkapkg:maven/org.apache.kafka/kafka-clients
< 2.8.0-r7+ 21 more
- (no CPE)range: < 2.8.0-r7
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.1-r1
- (no CPE)range: < 3.5.1-r1
- (no CPE)range: < 3.5.1-r1
- (no CPE)range: < 2.8.0-r7
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.0-r3
- (no CPE)range: < 3.5.1-r1
- (no CPE)range: < 3.5.1-r1
- (no CPE)range: < 3.5.1-r1
- (no CPE)range: >= 4.1.0, < 4.1.2
- (no CPE)range: >= 4.1.0, < 4.1.2
Patches
Vulnerability mechanics
References
6- github.com/advisories/GHSA-28jg-cgg7-j4wcghsaADVISORY
- kafka.apache.org/cve-listnvdVendor AdvisoryWEB
- lists.apache.org/thread/v57o00hm6yszdpdnvqx2ss4561yh953hnvdVendor AdvisoryMitigationWEB
- nvd.nist.gov/vuln/detail/CVE-2026-33557ghsaADVISORY
- www.openwall.com/lists/oss-security/2026/04/17/2nvdMailing ListWEB
- github.com/apache/kafka/commit/01d8e7db8d08dbd538892b409457ea6bfcc2a422ghsaWEB
News mentions
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