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Fencer Vulns
high 8.7

CVE-2026-35554 json

Apache Kafka Clients: Kafka Producer Message Corruption and Misrouting via Buffer Pool Race Condition

published 2026-04-07 7 mo ago modified 2026-10-26 13 d ago also GHSA-5qcv-4rpc-jp93 , EUVD-2026-19631

cvss
8.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

A race condition in the Apache Kafka Java producer client’s buffer pool management can cause messages to be silently delivered to incorrect topics.

When a produce batch expires due to delivery.timeout.ms while a network request containing that batch is still in flight, the batch’s ByteBuffer is prematurely deallocated and returned to the buffer pool. If a subsequent producer batch—potentially destined for a different topic—reuses this freed buffer before the original network request completes, the buffer contents may become corrupted. This can result in messages being delivered to unintended topics without any error being reported to the producer.

Data Confidentiality: Messages intended for one topic may be delivered to a different topic, potentially exposing sensitive data to consumers who have access to the destination topic but not the intended source topic.

Data Integrity: Consumers on the receiving topic may encounter unexpected or incompatible messages, leading to deserialization failures, processing errors, and corrupted downstream data.

This issue affects Apache Kafka versions ≤ 3.9.1, ≤ 4.0.1, and  ≤ 4.1.1.

Kafka users are advised to upgrade to 3.9.2, 4.0.2, 4.1.2, 4.2.0, or later to address this vulnerability.

Patch / fix

  • maven org.apache.kafka:kafka-clients 3.9.2, 4.0.2, 4.1.2
  • apache kafka 3.9.2, 4.0.2, 4.1.2

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-35554 updated cvss 6.8

Apache Kafka Clients: Apache Kafka Clients: Information disclosure and data corruption due to race condition in producer buffer management

  • Red Hat OpenShift Serverless openshift-serverless-1/kn-ekb-receiver-rhel9, openshift-serverless-1/kn-ekb-dispatcher-rhel9 Red Hat build of Apache Camel 4 for Quarkus 3 kafka-clients
    affected: workaround, no fix available
  • Red Hat build of Apicurio Registry 2 kafka-clients
    affected: workaround, no fix planned “Will not fix”
  • Red Hat build of Apicurio Registry 3 kafka-clients
    affected: workaround, no fix available
  • Red Hat build of Debezium 2 kafka-clients
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat build of Debezium 3 kafka-clients
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Fuse 7 kafka-clients Red Hat JBoss Enterprise Application Platform 7 kafka-clients
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat JBoss Enterprise Application Platform Expansion Pack kafka-clients
    affected: workaround, no fix available
  • Red Hat Process Automation 7 kafka-clients Red Hat streams for Apache Kafka 2 kafka-clients
    affected: workaround, no fix planned “Out of support scope”
show 8 more
  • Red Hat Build of Apache Camel 4.14 for Quarkus 3.27
    fixed: vendor fix RHSA-2026:13631
  • Red Hat build of Apache Camel 4.18.1 for Spring Boot 3.5.14
    fixed: vendor fix RHSA-2026:17668
  • Red Hat build of Quarkus 3.27.3.SP1 kafka-clients 4.0.2.redhat-00001
    fixed: vendor fix RHSA-2026:11721
  • Red Hat JBoss Enterprise Application Platform 6.0.5.GA kafka-clients 3.9.2.redhat-00001
    fixed: vendor fix RHSA-2026:42098
  • Red Hat Streams for Apache Kafka 3.2.1
    fixed: vendor fix RHSA-2026:54435
  • Red Hat build of Quarkus 3.27.3.SP1 jna 5.8.0, db2 1.21.4, h2 2.3.230, y18n 5.0.8, cliui 8.0.1, guice 5.1.0, +1005 more
    not affected: vulnerable code not present
  • Red Hat Data Grid 8 kafka-clients
    not affected: component not present
  • Red Hat Enterprise Linux 8 log4j, log4j-jcl, log4j-web, log4j-slf4j Red Hat Enterprise Linux 9 log4j, log4j-jcl, log4j-slf4j Red Hat JBoss Enterprise Application Platform 6.0.5.GA pom.xml, liblz4-java.so, libsnappyjava.so, jctools-core 4.0.5, commons-logging 1.2, wc-chatbot-0.1.2.jar, +263 more Red Hat JBoss Enterprise Application Platform 8 kafka-clients
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
CNA 3.1 8.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
GitHub 3.1 8.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
maven org.apache.kafka:kafka-clients
>=2.8.0, <3.9.2
>=4.0.0, <4.0.2
>=4.1.0, <4.1.2
3.9.2
4.0.2
4.1.2

Affected products

  • Apache Software Foundation Apache Kafka Clients

Classification

Weakness
  • CWE-416 Use After Free
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.