CVE-2026-42580

Name: CVE-2026-42580
Creator: NVD / NIST
Published: 2026-05-13T19:17:23.49+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.36%

Last modified Jun 17, 2026

CVE-2026-42580 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's chunk size parser silently overflows int, enabling request smuggling attacks. EPSS estimates a 0.36% chance of exploitation in the next 30 days.

Description

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's chunk size parser silently overflows int, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

0.36%

28.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Netty	Netty	< 4.1.133
Netty	Netty	>= 4.2.0, < 4.2.13

References

https://github.com/netty/netty/security/advisories/GHSA-m4cv-j2px-7723Exploit, Vendor Advisory
https://github.com/netty/netty/security/advisories/GHSA-m4cv-j2px-7723Exploit, Vendor Advisory

Timeline

Published: May 13, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-42580?

How severe is CVE-2026-42580?

CVE-2026-42580 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.36% probability of exploitation in the next 30 days.

How do I fix CVE-2026-42580?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-42580?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST