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HIGH severity

CVE-2026-41731 — spring-kafka

HIGH

CVE-2026-41731 is a high-severity (CVSS 8.1) Deserialization of Untrusted Data vulnerability in org.springframework.kafka:spring-kafka. A fix is available for org.springframework.kafka:spring-kafka — see the affected versions and patch details below.

In Spring for Apache Kafka, overly broad trusted-package matching in header mappers exposes JDK classes to deserialization

Also known asGHSA-xq69-5h5v-x9x4
Published
Jun 9, 2026
Updated
Sep 9, 2026
Affected
5 pkgs
Patched
2 / 5
Exploits
None indexed
Exploitation data as of Sep 27, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-41731.

EPSS Exploitation Probability

via FIRST.org ↗
0.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs49th percentile — riskier than 49% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-41731 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

5 pkgs affected
☕org.springframework.kafka:spring-kafka☕org.springframework.kafka:spring-kafka☕org.springframework.kafka:spring-kafka☕org.springframework.kafka:spring-kafka☕org.springframework.kafka:spring-kafka

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

JsonKafkaHeaderMapper and the deprecated DefaultKafkaHeaderMapper matched type headers against trusted packages using a prefix check, meaning that trusting any package implicitly trusted all of its subpackages. Combined with Jackson's default bean deserialization, a producer could supply crafted header values that caused the consumer to deserialize arbitrary JDK types.

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.

Affected Packages

5 total 2 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.springframework.kafka:spring-kafka≥ 4.0.0&&< 4.0.64.0.6org.springframework.kafka:spring-kafka:4.0.6
☕Mavenorg.springframework.kafka:spring-kafka≥ 3.3.0&&< 3.3.163.3.16org.springframework.kafka:spring-kafka:3.3.16
☕Mavenorg.springframework.kafka:spring-kafka≥ 3.2.0No fix
☕Mavenorg.springframework.kafka:spring-kafka≥ 2.9.0No fix
☕Mavenorg.springframework.kafka:spring-kafkaall versionsNo fix

Affected Products

3 products · 7 configurations
Application
fuseredhat
1 version
7.0.0
Application
jboss enterprise application platform expansion packredhat
all
Application
spring for apache kafkavmware
≥ 4.0.0 && < 4.0.5.1
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.springframework.kafka:spring-kafka, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.springframework.kafka:spring-kafka to 4.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-41731 is resolved across your whole dependency graph.

  3. Workarounds

    Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant
Workaround published by Red Hat
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Source: Red Hat security advisory for CVE-2026-41731 (CC BY 4.0)

Frequently Asked Questions

JsonKafkaHeaderMapper and the deprecated DefaultKafkaHeaderMapper matched type headers against trusted packages using a prefix check, meaning that trusting any package implicitly trusted all of its subpackages. Combined with Jackson's default bean deserialization, a producer could supply crafted header values that caused the consumer to deserialize arbitrary JDK types. 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.
O3 Security · Impact-Aware SCA

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CVE-2026-41731: spring-kafka (High 8.1) | O3 Security