9.1
CRITICAL
CVSS 3.1
CVE-2026-33557
Apache Kafka: Missing JWT token validation in OAUTHBEARER authentication
Overview
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.
Details
INFO
Published Date :
April 20, 2026, 2:16 p.m.
Last Modified :
July 15, 2026, 2:20 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework
for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | CRITICAL | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | ||||
| CVSS 3.1 | HIGH | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c |
Solution
Configure JWT validation and update Apache Kafka to a patched version.
- Set sasl.oauthbearer.jwt.validator.class to BrokerJwtValidator.
- Update Apache Kafka to v4.1.2 or later.
- Explicitly configure JWT token validation.
Public PoC/Exploit Available at Github
CVE-2026-33557 has a 2 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-33557.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-33557 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-33557
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
Python
Updated: 2 months, 3 weeks ago
0 stars
0 fork
0 watcher
Born at : April 28, 2026, 8:32 p.m.
This repo has been linked 15 different CVEs too.
None
Python YARA Dockerfile HTML C Shell Java JavaScript Lua PowerShell
Updated: 3 days, 11 hours ago
20 stars
1 fork
1 watcher
Born at : Dec. 15, 2025, 7:42 a.m.
This repo has been linked 19 different CVEs too.
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-33557 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-33557 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jul. 15, 2026
Action Type Old Value New Value Changed Affected [{'cpes': ['cpe:/a:redhat:debezium:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Debezium 3', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:amq_streams:3'], 'vendor': 'Red Hat', 'product': 'streams for Apache Kafka 3', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:serverless:1'], 'vendor': 'Red Hat', 'product': 'OpenShift Serverless', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:camel_quarkus:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apache Camel 4 for Quarkus 3', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:camel_spring_boot:4'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apache Camel for Spring Boot 4', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:service_registry:2'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apicurio Registry 2', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:apicurio_registry:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apicurio Registry 3', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:debezium:2'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Debezium 2', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:quarkus:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Quarkus', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_data_grid:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Data Grid 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_fuse:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Fuse 7', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_application_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform 7', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_application_platform:8'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jbosseapxp'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform Expansion Pack', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_bpms_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Process Automation 7', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:amq_streams:2'], 'vendor': 'Red Hat', 'product': 'streams for Apache Kafka 2', 'defaultStatus': 'unaffected'}] [{'cpes': ['cpe:/a:redhat:serverless:1'], 'vendor': 'Red Hat', 'product': 'OpenShift Serverless', 'packageName': 'openshift-serverless-1/kn-ekb-dispatcher-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:serverless:1'], 'vendor': 'Red Hat', 'product': 'OpenShift Serverless', 'packageName': 'openshift-serverless-1/kn-ekb-receiver-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:camel_quarkus:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apache Camel 4 for Quarkus 3', 'packageName': 'kafka-clients', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:camel_spring_boot:4'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apache Camel for Spring Boot 4', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:camel_spring_boot:4'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apache Camel for Spring Boot 4', 'packageName': 'kafka-clients', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:service_registry:2'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apicurio Registry 2', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:apicurio_registry:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apicurio Registry 3', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:debezium:2'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Debezium 2', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:debezium:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Debezium 3', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:quarkus:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Quarkus', 'packageName': 'kafka-clients', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_data_grid:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Data Grid 8', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_data_grid:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Data Grid 8', 'packageName': 'kafka-clients', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'packageName': 'log4j:2/log4j', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'packageName': 'log4j', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_fuse:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Fuse 7', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_fuse:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Fuse 7', 'packageName': 'kafka-clients', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_application_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform 7', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_application_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform 7', 'packageName': 'kafka-clients', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_application_platform:8'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform 8', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_application_platform:8'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform 8', 'packageName': 'kafka-clients', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jbosseapxp'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform Expansion Pack', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jbosseapxp'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform Expansion Pack', 'packageName': 'kafka-clients', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_bpms_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Process Automation 7', 'packageName': 'kafka-clients', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:amq_streams:2'], 'vendor': 'Red Hat', 'product': 'streams for Apache Kafka 2', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:amq_streams:2'], 'vendor': 'Red Hat', 'product': 'streams for Apache Kafka 2', 'packageName': 'kafka-clients', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:amq_streams:3'], 'vendor': 'Red Hat', 'product': 'streams for Apache Kafka 3', 'packageName': 'connect-api', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:amq_streams:3'], 'vendor': 'Red Hat', 'product': 'streams for Apache Kafka 3', 'packageName': 'kafka-clients', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}] -
CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jun. 30, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:/a:redhat:debezium:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Debezium 3', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:amq_streams:3'], 'vendor': 'Red Hat', 'product': 'streams for Apache Kafka 3', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:serverless:1'], 'vendor': 'Red Hat', 'product': 'OpenShift Serverless', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:camel_quarkus:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apache Camel 4 for Quarkus 3', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:camel_spring_boot:4'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apache Camel for Spring Boot 4', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:service_registry:2'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apicurio Registry 2', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:apicurio_registry:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Apicurio Registry 3', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:debezium:2'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Debezium 2', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:quarkus:3'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Quarkus', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_data_grid:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Data Grid 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:9'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 9', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_fuse:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Fuse 7', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_application_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform 7', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_application_platform:8'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform 8', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jbosseapxp'], 'vendor': 'Red Hat', 'product': 'Red Hat JBoss Enterprise Application Platform Expansion Pack', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:jboss_enterprise_bpms_platform:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Process Automation 7', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:amq_streams:2'], 'vendor': 'Red Hat', 'product': 'streams for Apache Kafka 2', 'defaultStatus': 'unaffected'}] Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L Added CWE CWE-303 Added Reference https://access.redhat.com/security/cve/CVE-2026-33557 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2459739 Added Reference https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33557.json -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Apache Software Foundation', 'product': 'Apache Kafka', 'versions': [{'status': 'affected', 'version': '4.1.0', 'versionType': 'semver', 'lessThanOrEqual': '4.1.1'}], 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-33557', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-04-20T14:29:31.424817Z'} -
Initial Analysis by [email protected]
Apr. 22, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:apache:kafka:*:*:*:*:*:*:*:* versions from (including) 4.1.0 up to (excluding) 4.1.2 Added Reference Type Apache Software Foundation: https://kafka.apache.org/cve-list Types: Vendor Advisory Added Reference Type Apache Software Foundation: https://lists.apache.org/thread/v57o00hm6yszdpdnvqx2ss4561yh953h Types: Mitigation, Vendor Advisory Added Reference Type CVE: http://www.openwall.com/lists/oss-security/2026/04/17/2 Types: Mailing List -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Apr. 20, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N -
New CVE Received by [email protected]
Apr. 20, 2026
Action Type Old Value New Value Added 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. Added CWE CWE-1285 Added Reference https://kafka.apache.org/cve-list Added Reference https://lists.apache.org/thread/v57o00hm6yszdpdnvqx2ss4561yh953h -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Apr. 20, 2026
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2026/04/17/2
EPSS is a daily estimate of the probability of exploitation activity
being observed over the next 30 days. Following chart shows the EPSS
score history of the vulnerability.