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CVE-2026-35554· NVD / CVE Program· CNA apache

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

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.

HighCVSS 8.7 · v3.1—No exploit Fix available
Published
Apr 7, 2026
Updated
Aug 17, 2026
EPSS
0.6% · 49th percentile
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Report tools

JSON

Action score

34

Monitor

Low priority for now.

CVSS
34 / 40 · 8.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Affected systems

VendorProduct
apachekafka

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • apache kafka2.8.0 and later · before 3.9.2
  • apache kafka4.0.0 and later · before 4.0.2
  • apache kafka4.1.0 and later · before 4.1.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.

  • Apache Software Foundation Apache Kafka Clients

    • 2.8.0 and later · up to and including 3.9.1affected · semver
    • 4.0.0 and later · up to and including 4.0.1affected · semver
    • 4.1.0 and later · up to and including 4.1.1affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Mavenorg.apache.kafka:kafka-clientsfrom 2.8.0 · before 3.9.23.9.2
Mavenorg.apache.kafka:kafka-clientsfrom 4.0.0 · before 4.0.24.0.2
Mavenorg.apache.kafka:kafka-clientsfrom 4.1.0 · before 4.1.24.1.2

Same product

apache: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-27817Apache Kafka Client: Arbitrary file read and SSRF vulnerability
    51Plan
  • CVE-2018-17196In Apache Kafka versions between 0.11.0.0 and 2.1.0, it is possible to manually craft a Produce request which bypasses transaction/idempoten
    37Monitor
  • CVE-2026-33557Apache Kafka: Missing JWT token validation in OAUTHBEARER authentication
    36Monitor
  • CVE-2025-27818Apache Kafka: Possible RCE attack via SASL JAAS LdapLoginModule configuration
    35Monitor
  • CVE-2019-12399When Connect workers in Apache Kafka 2.0.0, 2.0.1, 2.1.0, 2.1.1, 2.2.0, 2.2.1, or 2.3.0 are configured with one or more config providers, an
    31Monitor
  • CVE-2025-27819Apache Kafka: Possible RCE/Denial of service attack via SASL JAAS JndiLoginModule configuration
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Maven:org.apache.kafka:kafka-clients3.9.2Package registry (OSV)
Maven:org.apache.kafka:kafka-clients4.0.2Package registry (OSV)
Maven:org.apache.kafka:kafka-clients4.1.2Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

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Change log

  1. Fix✗ → ✓

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References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records