CVE-2026-41731Network attack vector

Arbitrary JDK-type deserialization via package-prefix trust

Published Jun 9, 2026 · Updated Jun 9, 2026

Deserialization in Spring for Apache Kafka allows remote attackers to instantiate arbitrary JDK types through crafted Kafka headers. JsonKafkaHeaderMapper and DefaultKafkaHeaderMapper use a prefix comparison for trusted packages, so a trusted package also admits every subpackage to Jackson's default bean deserializer. A producer able to send records to the consumer can trigger constructors with side effects, including file-descriptor allocation and thread-pool creation.

CVSS severity8.1
High
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in Spring for Apache Kafka allows remote attackers to instantiate arbitrary JDK types through crafted Kafka headers. JsonKafkaHeaderMapper and DefaultKafkaHeaderMapper use a prefix comparison for trusted packages, so a trusted package also admits every subpackage to Jackson's default bean deserializer. A producer able to send records to the consumer can trigger constructors with side effects, including file-descriptor allocation and thread-pool creation.

The record

CVE
CVE-2026-41731
Published
Jun 9, 2026
Updated
Jun 9, 2026
Vendor
Spring
Product
Spring for Apache Kafka
Classifications
CWE-502
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 9, 2026CVE publishedPublication date reported by the CVE source.
  2. 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.

  1. Affected versionversion=2.8.0 <2.8.12
  2. Affected versionversion=2.9.0 <2.9.14
  3. Affected versionversion=3.2.0 <3.2.14
  4. Affected versionversion=3.3.0 <3.3.16
  5. Affected versionversion=4.0.0 <4.0.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Spring · Spring for Apache Kafkaversion=2.8.0 <2.8.12; version=2.9.0 <2.9.14; version=3.2.0 <3.2.14; version=3.3.0 <3.3.16; version=4.0.0 <4.0.6

Published CVSS scores

8.1VMwareCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1Red HatCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data

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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