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.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00028.

Exploitation poc

Automatable yes

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
netty netty affected
Version Status Constraints
>= 4.2.0.Alpha1, < 4.2.8.Final affected —
< 4.1.129.Final affected —

Configuration 1 [-]

OR cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*

No data.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-84h7-rjj3-6jx4 Netty has a CRLF Injection vulnerability in io.netty.handler.codec.http.HttpRequestEncoder
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/netty/netty/security/advisories/GHSA-84h7-rjj3-6jx4 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-67735 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-67735 cve-icon
History

Fri, 02 Jan 2026 19:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*

Wed, 17 Dec 2025 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 threat_severity

Moderate

Tue, 16 Dec 2025 17:15:00 +0000

Type Values Removed Values Added
First Time appeared Netty
Netty netty
Vendors & Products Netty
Netty netty

Tue, 16 Dec 2025 15:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 16 Dec 2025 00:45:00 +0000

Type Values Removed Values Added
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.
Title Netty has a CRLF Injection vulnerability in io.netty.handler.codec.http.HttpRequestEncoder
Weaknesses CWE-93
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2025-12-16T14:26:48.934Z

Reserved: 2025-12-11T00:45:45.790Z

Link: CVE-2025-67735

cve-icon Vulnrichment

Updated: 2025-12-16T14:26:45.280Z

cve-icon NVD

Status : Analyzed

Published: 2025-12-16T01:15:52.367

Modified: 2026-01-02T18:50:23.313

Link: CVE-2025-67735

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-12-16T00:19:11Z

Links: CVE-2025-67735 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-12-16T17:09:37Z

Weaknesses