CVE-2026-33870

Name: CVE-2026-33870
Creator: NVD / NIST
Published: 2026-03-27T20:16:34.663+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.46%

Last modified Jun 17, 2026

CVE-2026-33870 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, Netty incorrectly parses quoted strings in HTTP/1.1 chunked transfer encoding extension values, enabling request smuggling attacks. EPSS estimates a 0.46% chance of exploitation in the next 30 days.

Description

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, Netty incorrectly parses quoted strings in HTTP/1.1 chunked transfer encoding extension values, enabling request smuggling attacks. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

0.46%

36.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-444

Affected Software

Vendor	Product	Versions
Netty	Netty	< 4.1.132
Netty	Netty	>= 4.2.0, < 4.2.10

References

https://github.com/netty/netty/security/advisories/GHSA-pwqr-wmgm-9rr8Exploit, Mitigation, Vendor Advisory
https://w4ke.info/2025/06/18/funky-chunks.htmlTechnical Description
https://w4ke.info/2025/10/29/funky-chunks-2.htmlTechnical Description
https://www.rfc-editor.org/rfc/rfc9110Technical Description

Timeline

Published: Mar 27, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-33870?

How severe is CVE-2026-33870?

CVE-2026-33870 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.46% probability of exploitation in the next 30 days.

How do I fix CVE-2026-33870?

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-2026-33870?

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

Scan your code now

Source: NVD / NIST