Spring For Apache KafkaWeb server / proxy · VMware
CVE-2026-41726
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedWhen an application opts into DelegatingDeserializer, a producer can grow the consumer's heap without bound by sending records with unique random spring.kafka.serialization.selector header values, eventually causing GC thrash and OutOfMemoryError. Affected versions: Spring for Apache Kafka 4.0.0 through 4.0.5; 3.3.0 through 3.3.15; 3.2.0 through 3.2.13; 2.9.0 through 2.9.13; 2.8.0 through 2.8.11.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA denial of service vulnerability in Spring for Apache Kafka's DelegatingDeserializer allows a producer to cause unbounded heap growth by sending records with unique random spring.kafka.serialization.selector header values. The deserializer caches these selector values without bounds, leading to GC thrash and eventual OutOfMemoryError.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Spring For Apache KafkaWeb server / proxy
< 2.8.12>= 2.9.0, < 2.9.14>= 3.2.0, < 3.2.14>= 3.3.0, < 3.3.15.1>= 4.0.0, < 4.0.5.1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify DelegatingDeserializer usage in Kafka configurationSearch configuration files (application.yml, application.properties) and Java configuration classes for 'DelegatingDeserializer' or the property 'spring.kafka.consumer.properties.spring.kafka.serialization.selector' or similar configurations that use header-based deserializer selection.Affected if DelegatingDeserializer is configured as the key or value deserializer for Kafka consumers or producers.
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Verify inbound Kafka record processingReview Kafka consumer code that deserializes records. Look for @KafkaListener methods or KafkaConsumer usage that deserializes using headers, particularly where the deserializer reads from record headers.Affected if The application consumes Kafka records and uses a deserializer that reads the 'spring.kafka.serialization.selector' header from incoming records.
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Check for external header input exposureExamine whether Kafka record headers could be controlled by external producers. Review if the application processes records from topics that accept submissions from untrusted sources.Affected if The application processes Kafka records from topics where producers can set arbitrary header values without validation.
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Monitor for unusual deserializer instantiation patternsEnable debug logging for org.apache.kafka.common.serialization.Deserializer implementations. Monitor JVM heap usage and object creation rates during Kafka message processing.Affected if Heap usage grows continuously or GC frequency increases significantly while processing Kafka records with varying header values.
You are affected if your Kafka consumers use DelegatingDeserializer and process records from topics where external producers can set arbitrary 'spring.kafka.serialization.selector' header values.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped2.8.122.9.143.2.14
Upgrade to patched versions of Spring for Apache Kafka (4.0.6+, 3.3.16+, 3.2.14+, 2.9.14+, 2.8.12+) or implement header value limiting/validation in custom deserializer implementations to prevent unbounded caching.
Upgrade to 2.8.12, 2.9.14, 3.2.14, 3.3.15.1, or 4.0.6 (or later) depending on your current version branch
- 1. Identify the current Spring for Apache Kafka version in your project (check pom.xml, build.gradle, or dependency management)
- 2. Determine which version branch you are currently on (2.8.x, 2.9.x, 3.2.x, 3.3.x, or 4.0.x)
- 3. Upgrade to the minimum fixed version for your branch: for 2.8.x upgrade to 2.8.12; for 2.9.x upgrade to 2.9.14; for 3.2.x upgrade to 3.2.14; for 3.3.x upgrade to 3.3.15.1; for 4.0.x upgrade to 4.0.6
- 4. Update the spring-kafka dependency version in your build configuration
- 5. Rebuild and test your application to ensure the upgrade does not introduce regressions
- 6. If using DelegatingDeserializer specifically, verify the fix is working by monitoring heap usage under load
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Spring For Apache Kafka
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-41726 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-41726 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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