Vulnerability in Netty

CVE-2026-41417

Netty allows request-line validation to be bypassed when a `DefaultHttpRequest` or `DefaultFullHttpRequest` is created first and its URI is later changed via `setUri()`. The constructors reject CRLF and whitespace characters that would break the start-line, but `setUri()` does not apply the same validation. `HttpRequestEncoder` and `RtspEncoder` then write the URI into the request line verbatim. If attacker-controlled input reaches `setUri()`, this enables CRLF injection and insertion of additional HTTP or RTSP requests, leading to HTTP request smuggling or desynchronization on the HTTP side and request injection on the RTSP side. This issue is fixed in versions 4.2.13.Final and 4.1.133.Final.

Vulnerability class: CRLF Injection

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (24.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 24th percentile — 24.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-41417: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000

Affected products

  • Netty — versions >= 4.2.0.Alpha1, <= 4.2.12.Final, <= 4.1.132.Final

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-41417?
CVE-2026-41417 is a medium-severity vulnerability in Netty, classified under CRLF Injection. CVSS score: 5.3/10. Published 2026-05-06.
How severe is CVE-2026-41417?
Medium severity. CVSS v3 base score is 5.3 out of 10.