CVE-2025-67735: Netty has a CRLF Injection vulnerability in io.netty.handler.codec.http.HttpRequestEncoder

CVE-2025-67735 · Severity: medium · CVSS 6.5 · Published 2025-12-16

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.129.Final and 4.2.8.Final, the `io.netty.handler.codec.http.HttpRequestEncoder` has a CRLF injection with the request URI when constructing a request. This leads to request smuggling when `HttpRequestEncoder` is used without proper sanitization of the URI. Any application / framework using `HttpRequestEncoder` can be subject to be abused to perform request smuggling using CRLF injection. Versions 4.1.129.Final and 4.2.8.Final fix the issue.

Technologies: io.netty:netty-codec-http (Maven), Netty. Vendors: Maven, Netty.

Quick answers

Is CVE-2025-67735 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-67735 being exploited in the wild.
How severe is CVE-2025-67735?
Medium severity, with a CVSS score of 6.5, published 16 December 2025.
Which products and versions are affected?
io.netty:netty-codec-http (Maven) ECOSYSTEM:introduced=4.2.0.Alpha1,fixed=4.2.8.Final.
Is there a fix for CVE-2025-67735?
Yes. io.netty:netty-codec-http (Maven): upgrade to 4.2.8.Final or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2025-67735?
Check whether you run io.netty:netty-codec-http (Maven) or Netty at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • io.netty:netty-codec-http (Maven): upgrade to 4.2.8.Final or later
    # set io.netty:netty-codec-http to 4.2.8.Final in your pom.xml or build.gradle

Affected products

  • io.netty:netty-codec-http (Maven) ECOSYSTEM:introduced=4.2.0.Alpha1,fixed=4.2.8.Final
  • Netty

Identifiers

  • CVE-2025-67735
  • GHSA-84h7-rjj3-6jx4

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