How severe is CVE-2023-34040?

CVE-2023-34040 has a CVSS score of 7.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2023-34040?

CVE-2023-34040 affects the following packages: org.springframework.kafka:spring-kafka (Maven), org.springframework.kafka:spring-kafka (Maven). Ecosystems affected: Maven.

How do I fix CVE-2023-34040?

Update org.springframework.kafka:spring-kafka to 2.9.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-34040 is resolved across your whole dependency graph.

How do I detect CVE-2023-34040 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.springframework.kafka:spring-kafka. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2023-34040 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2023-34040?

O3 pinpoints whether CVE-2023-34040 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2023-34040 actively exploited in the wild?

Yes. There are 4 known exploit references for CVE-2023-34040, including 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2023-34040?

CVE-2023-34040 has an EPSS (Exploit Prediction Scoring System) score of 2.2%, placing it in the 80th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-34040?

CVE-2023-34040 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2023-34040 published, and has it been updated?

CVE-2023-34040 was published on August 24, 2023 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

CVE-2023-34040

HIGH

Spring-Kafka has Java Deserialization vulnerability When Improperly Configured

Also known asGHSA-crqf-q9fp-hwjw

Published

Aug 24, 2023

Updated

Apr 10, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

4 known

EPSS Exploitation Probability

via FIRST.org ↗

2.2%probability of exploitation in next 30 days

Lower Risk80th percentile-19.25%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

2 pkgs affected

☕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

Specifically, an application is vulnerable when all of the following are true:

The user does not configure an ErrorHandlingDeserializer for the key and/or value of the record
The user explicitly sets container properties checkDeserExWhenKeyNull and/or checkDeserExWhenValueNull container properties to true.
The user allows untrusted sources to publish to a Kafka topic

By default, these properties are false, and the container only attempts to deserialize the headers if an ErrorHandlingDeserializer is configured. The ErrorHandlingDeserializer prevents the vulnerability by removing any such malicious headers before processing the record.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.springframework.kafka:spring-kafka`	≥ 2.8.1&&< 2.9.11	2.9.11
☕Maven	`org.springframework.kafka:spring-kafka`	≥ 3.0.0&&< 3.0.10	3.0.10

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

In Spring for Apache Kafka 3.0.9 and earlier and versions 2.9.10 and ear…

github.comGithubAug 2023

In Spring for Apache Kafka 3.0.9 and earlier and versions 2.9.10 and ear…

github.comGithubSep 2023

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.springframework.kafka:spring-kafka. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.springframework.kafka:spring-kafka to 2.9.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-34040 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2023-34040 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2023-34040. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

In Spring for Apache Kafka 3.0.9 and earlier and versions 2.9.10 and earlier, a possible deserialization attack vector existed, but only if unusual configuration was applied. An attacker would have to construct a malicious serialized object in one of the deserialization exception record headers. Specifically, an application is vulnerable when all of the following are true: * The user does not configure an ErrorHandlingDeserializer for the key and/or value of the record * The user explicitly sets container properties checkDeserExWhenKeyNull and/or checkDeserExWhenValueNull container pro

O3 Security · Impact-Aware SCA

Is CVE-2023-34040 in your dependencies?

O3 detects CVE-2023-34040 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works