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. EPSS exploitation probability: 0.0%.

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

LOW

HTTP Request/Response Smuggling (CWE-444)

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

Information Disclosure Request Smuggling Netty

2.9

CVSS 4.0 · Vendor: github

View

Vulnerability Assessment

Weakness	CWE CWE-444 OWASP Top 10:2025 A06:2025 - Insecure Design ASVS 5.0 V4 - API and Web Service HTTP request consistency
Impact	CVSS score of 2.9 (LOW). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available. EPSS exploitation probability: 0.03%.
Exploit ScenarioDerived	A remote attacker could manipulate HTTP request interpretation between frontend and backend servers by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

Monitor Track and reassess. Why: LOW severity (CVSS 0.1-3.9).

Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

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.

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.

Affected Packages

maven io.netty:netty-codec-http fix: 4.1.125.Final, 4.2.5.Final

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in maven

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

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..

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (github) 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

Primary rating from Vendor (github) · only source for this CVE.

CVSS VectorVendor: github

Attack Vector

Network

Attack Complexity

Low

Attack Requirements

Present

Privileges Required

None

User Interaction

None

Vulnerable system: Confidentiality

None

Vulnerable system: Integrity

Low

Vulnerable system: Availability

None

Subsequent system: Confidentiality

None

Subsequent system: Integrity

None

Subsequent system: Availability

None

Lifecycle Timeline

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

DescriptionCVE.org

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.

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.

Executive ViewAI

Why It Matters

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 and can be applied during standard maintenance windows.

Business Impact: Low

Compensating Controls

Apply vendor patch during routine maintenance. Standard security controls provide adequate interim protection.

Threat Intelligence Overview

EPSS Score

0.0%

Top 90% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity LOW

CISA KEV No

Public POC Yes

EPSS 0.0%

Patch available Yes

Active threat No

Deciding rule

LOW severity (CVSS 0.1-3.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

Low

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +14

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

HTTP Request Smuggling HIGH

HTTP request smuggling exploits inconsistencies in how front-end and back-end servers parse HTTP message boundaries.

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.