CVE-2025-67735
Netty has a CRLF Injection vulnerability in io.netty.handler.codec.http.HttpRequestEncoder
Description
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.
How to fix CVE-2025-67735
To remediate CVE-2025-67735, upgrade the affected package to a fixed version below.
- —upgrade to 1:4.1.48-4+deb11u3 or later
- —upgrade to 4.2.8.Final or later
Is CVE-2025-67735 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 1:4.1.48-4+deb11u3
- >= 4.2.0.Alpha1, < 4.2.8.Final
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |