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🛡️ CVE-2026-35554 — kafka

🟠 CVSS 8.7 — High ✅ No Known Exploit CWE-362 NVD
8.7
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality high, integrity high, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Changed — a successful attack reaches components beyond the vulnerable one.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Weakness class

CVE-2026-35554 is classified as CWE-362: Race Condition. Concurrent operations share state without proper synchronisation, so timing decides whether the result is correct.

Affected software

CVE-2026-35554 is recorded against 2 packages.

  • kafka (from 4.1.0 up to 4.1.2)
  • org.apache.kafka:kafka-clients (from 4.1.0 up to 4.1.2)

Timeline and source

Published on 7 April 2026 and last revised on 17 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

issues.apache.org
lists.apache.org
www.openwall.com

Other advisories for this package

kafka has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-362: Race Condition) in other software:

CVE-2026-35554 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity HIGH
CVSS Score 8.7
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
CWE CWE-362
Public Exploit ✅ No
Source NVD
Published 2026-04-07
Updated 2026-08-20
Modified 2026-08-17
Fix URL N/A

Affected Packages

Software From version Fixed in
kafka 4.1.0 4.1.2
org.apache.kafka:kafka-clients 4.1.0 4.1.2

Site Security Check

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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