Authenticated consumer crash via unbounded delegate cache
Published Jun 9, 2026 · Updated Jun 9, 2026
Denial of service in Spring for Apache Kafka allows remote authenticated users to crash consumers by sending crafted Kafka records. DelegatingDeserializer stores a fallback deserializer in an unbounded ConcurrentHashMap for every distinct invalid selector header, retaining entries for the consumer's lifetime. Affected versions are 2.8.0 through 2.8.11, 2.9.0 through 2.9.13, 3.2.0 through 3.2.13, 3.3.0 through 3.3.15, and 4.0.0 through 4.0.5; exploitation requires producer access and explicit DelegatingDeserializer configuration, and heap growth ends in GC thrash and OutOfMemoryError.
Summary
What happened
Denial of service in Spring for Apache Kafka allows remote authenticated users to crash consumers by sending crafted Kafka records. DelegatingDeserializer stores a fallback deserializer in an unbounded ConcurrentHashMap for every distinct invalid selector header, retaining entries for the consumer's lifetime. Affected versions are 2.8.0 through 2.8.11, 2.9.0 through 2.9.13, 3.2.0 through 3.2.13, 3.3.0 through 3.3.15, and 4.0.0 through 4.0.5; exploitation requires producer access and explicit DelegatingDeserializer configuration, and heap growth ends in GC thrash and OutOfMemoryError.
The record
- CVE
- CVE-2026-41726
- Published
- Jun 9, 2026
- Updated
- Jun 9, 2026
- Vendor
- Spring
- Product
- Spring for Apache Kafka
- Classifications
- CWE-770, T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 9, 2026CVE publishedPublication date reported by the CVE source.
- Jun 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.8.0 <2.8.12
- Affected versionversion=2.9.0 <2.9.14
- Affected versionversion=3.2.0 <3.2.14
- Affected versionversion=3.3.0 <3.3.16
- Affected versionversion=4.0.0 <4.0.6
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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