CVE-2026-41727: Input Validation Flaw (CVSS 6.5)

Description

Spring Kafka's retry topic infrastructure did not sufficiently validate user-controlled header values before acting on them. A producer could send a record with a crafted retry_topic-attempts header to supply an out-of-range attempt count and cause the retry topic router to misidentify where the message was in the retry sequence. 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.

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CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0024

Probability of exploitation

0.15%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-20 Improper Input Validation

References

Other References

https://spring.io/security/cve-2026-41727

Frequently Asked Questions

What is CVE-2026-41727? +

Spring Kafka's retry topic infrastructure did not sufficiently validate user-controlled header values before acting on them. A producer could send a record with a crafted retry_topic-attempts header to supply an out-of-range attempt count and cause the retry topic router to misidentify where the message was in the retry sequence. 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. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-41727? +

CVE-2026-41727 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0024, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-41727? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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