CVE-2025-67735

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.

CVSS v3.1 Score

6.5

MEDIUM

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

Weakness Type (CWE)

CWE-93 CWE-93

Affected Products

Vendor	Product	Versions
netty	netty	< 4.1.129
netty	netty	4.2.0 — 4.2.8

References

Advisories & Patches

https://github.com/netty/netty/security/advisories/GHSA-84h7-rjj3-6jx4

Exploits

https://github.com/netty/netty/security/advisories/GHSA-84h7-rjj3-6jx4

Frequently Asked Questions

What is CVE-2025-67735? +

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. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2025-67735? +

CVE-2025-67735 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-67735? +

CVE-2025-67735 affects products from netty, specifically: netty. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-67735? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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