Which versions of Netty are affected by CVE-2025-58056?

CVE-2025-58056 is a low-severity vulnerability in Netty (CVSS 2.9). The limited severity suggests constrained impact, typically requiring specific conditions or local access for exploitation.. A patch is available.

Is there a public PoC exploit available for CVE-2025-58056?

Yes, a public proof-of-concept exploit is available for CVE-2025-58056. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2025-58056?

During next maintenance window: Apply vendor patches when convenient. Vendor patch is available.

Netty CVE-2025-58056

Q: What is the CVSS score of CVE-2025-58056?

CVE-2025-58056 has a CVSS 4.0 base score of 2.9 (Low). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

LOW

HTTP Request/Response Smuggling (CWE-444)

2025-09-03 security-advisories@github.com

Request Smuggling Information Disclosure Netty

2.9

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

2.9 LOW

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:10 vuln.today

Patch released

Mar 28, 2026 - 19:10 nvd

Patch available

PoC Detected

Sep 08, 2025 - 16:46 vuln.today

Public exploit code

CVE Published

Sep 03, 2025 - 21:15 nvd

LOW 2.9

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

11 maven packages depend on io.netty:netty-codec-http (11 direct, 0 indirect)

Ecosystem-wide dependent count for version 4.2.0.Alpha1.

DescriptionGitHub Advisory

Netty is an asynchronous event-driven network application framework for development of maintainable high performance protocol servers and clients. In versions 4.1.124.Final, and 4.2.0.Alpha3 through 4.2.4.Final, Netty incorrectly accepts standalone newline characters (LF) as a chunk-size line terminator, regardless of a preceding carriage return (CR), instead of requiring CRLF per HTTP/1.1 standards. When combined with reverse proxies that parse LF differently (treating it as part of the chunk extension), attackers can craft requests that the proxy sees as one request but Netty processes as two, enabling request smuggling attacks. This is fixed in versions 4.1.125.Final and 4.2.5.Final.

AnalysisAI

Netty is an asynchronous event-driven network application framework for development of maintainable high performance protocol servers and clients. Rated low severity (CVSS 2.9), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

Technical ContextAI

This vulnerability is classified as HTTP Request/Response Smuggling (CWE-444), which allows attackers to manipulate HTTP request interpretation between frontend and backend servers. Netty is an asynchronous event-driven network application framework for development of maintainable high performance protocol servers and clients. In versions 4.1.124.Final, and 4.2.0.Alpha3 through 4.2.4.Final, Netty incorrectly accepts standalone newline characters (LF) as a chunk-size line terminator, regardless of a preceding carriage return (CR), instead of requiring CRLF per HTTP/1.1 standards. When combined with reverse proxies that parse LF differently (treating it as part of the chunk extension), attackers can craft requests that the proxy sees as one request but Netty processes as two, enabling request smuggling attacks. This is fixed in versions 4.1.125.Final and 4.2.5.Final. Affected products include: Netty. Version information: through 4.2.4..

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Enforce strict HTTP parsing, normalize requests at proxy layer, use HTTP/2 end-to-end, reject ambiguous headers.