VulnerabilityPublished 28 Oct 2026

CVE-2026-111551: Apache Kafka · Excessive Memory Allocation

Affects Apache KafkaSource CVE Database V5

Not known to be exploited · fixed in 4.2.2 : patch Apache Kafka soon.

Data as of 28 Oct 2026, 17:23 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Patch: Available – fixed in 4.2.2

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Apache Kafkaorg.apache.kafka:kafka-streams	Affected >=0.10.0.0 <=4.1.2 >=4.2.0 <=4.2.1 >=4.3.0 <=4.3.1	Fixed in–
Apache Kafkaorg.apache.kafka:kafka-clients	Affected >=0.10.0.0 <=4.1.2 >=4.2.0 <=4.2.1 >=4.3.0 <=4.3.1	Fixed in–
MavenApache Software Foundation/org.apache.kafka:kafka-streams`pkg:maven/Apache Software Foundation/org.apache.kafka:kafka-streams`Other threats	Affected >=0.10.0.0 <=4.1.2 >=4.2.0 <=4.2.1 >=4.3.0 <=4.3.1	Fixed in–
MavenApache Software Foundation/org.apache.kafka:kafka-clients`pkg:maven/Apache Software Foundation/org.apache.kafka:kafka-clients`Other threats	Affected >=0.10.0.0 <=4.1.2 >=4.2.0 <=4.2.1 >=4.3.0 <=4.3.1	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade Apache Kafka to versions 4.2.2, 4.3.2, or 4.4.0 where the vulnerability is fixed by validating size fields before allocation. Additionally, if authorization is enabled, restrict write access to internal topics and consumer groups to their respective principals and limit who can produce to topics consumed with ListSerde. These measures reduce the attack surface and prevent unauthorized injection of crafted records.

Description

CVE-2026-111551 is a vulnerability in Apache Kafka where several deserialization paths allocate memory based on unvalidated size or count fields from input data. This can lead to excessive memory allocation, causing OutOfMemoryError and crashing the affected consumer or Kafka Streams thread. The issue affects Kafka versions up to 4.1.2, 4.2.1, and 4.3.1. The vulnerability is mitigated by upgrading to Apache Kafka 4.2.2, 4.3.2, or 4.4.0, which include validation of declared sizes before allocation.

Impact

An attacker can cause a denial of service by triggering excessive memory allocation leading to OutOfMemoryError and crashing Kafka consumer or Kafka Streams threads. This affects only the consumer or Streams client processes, not the Kafka broker or cluster. The crafted record causing the crash remains in the topic, allowing repeated crashes on restart. The vulnerability can be exploited by writing crafted records to internal changelog or repartition topics, committing crafted offset metadata, or producing to topics consumed with ListSerde. The record size limit does not prevent exploitation.

CWE-789Memory Allocation with Excessive Size Value (opens in a new tab)
Variant weakness
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
Implementation · Architecture and Design
Perform adequate input validation against any value that influences the amount of memory that is allocated. Define an appropriate strategy for handling requests that exceed the limit, and consider supporting a configuration option so that the administrator can extend the amount of memory to be used if necessary.
Operation
Run your program using system-provided resource limits for memory. This might still cause the program to crash or exit, but the impact to the rest of the system will be minimized.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-400Uncontrolled Resource Consumption (opens in a new tab)
Class weaknessLikelihood of exploit: High
The product does not properly control the allocation and maintenance of a limited resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place.
Architecture and Design
Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or; uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Architecture and Design
Ensure that protocols have specific limits of scale placed on them.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Regular Expression Exponential Blowup (opens in a new tab)
Sustained Client Engagement (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-20Improper Input Validation (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #18OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Attack Surface Reduction
Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build "recognizers" for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of…
Architecture and Design · Libraries or Frameworks
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Server Side Include (SSI) Injection (opens in a new tab)
Cross Zone Scripting (opens in a new tab)
Command Line Execution through SQL Injection (opens in a new tab)
Object Relational Mapping Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

kafka.apache.org/cve-list (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Oct 2026, 17:23 UTC

WeaknessesCWE-789, CWE-400, CWE-20

Technical details

References

Community reviews

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