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CVE-2025-58056

Netty vulnerability

7.5 HIGHPublic exploitEPSS 0.68%
  1. Published3 Sept 2025

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

Netty≥ 4.2.0 < 4.2.5 · < 4.1.125

Remediation

Fixed in
Netty≥ 4.2.5

References

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Frequently asked

Is CVE-2025-58056 being actively exploited?

CVE-2025-58056 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.68%.

How severe is CVE-2025-58056?

CVE-2025-58056 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.68% probability of exploitation.

Which products are affected by CVE-2025-58056?

Affected products include Netty.

How do I fix CVE-2025-58056?

Upgrade affected software to a fixed version, for example Netty 4.2.5 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.