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Vulnerabilities

Vulnerability · CVE-2026-42578

Netty is an asynchronous, event-driven network application framework.

Published May 13, 2026 · catalog updated Sep 18, 2026 · Netty is an asynchronous,

Check if you run it

No confirmed exploitation is on record for CVE-2026-42578. EPSS is 1.15%. Act only if a listed version of Netty is an asynchronous, is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Netty is an asynchronous,).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Low2.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.15%
Remediation
Advisory link
Affected products
cpe netty/netty

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using DefaultHttpHeadersFactory.headersFactory().withValidation(false), then adds user-provided outboundHeaders without any CRLF validation. This allows an attacker who can influence the outbound headers to inject arbitrary HTTP headers into the CONNECT request sent to the proxy server. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe netty/nettyversion unspecified

How to fix CVE-2026-42578

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-42578. EPSS is 1.15%. Act only if a listed version of Netty is an asynchronous, is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-113; CWE-93. EPSS 1.15%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. May 13, 2026 · NIST NVD

    Detected

    Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using DefaultHttpHeadersFactory.headersFactory().withValidation(false), then adds user-provided outboundHeaders without any CRLF validation.

  2. Sep 18, 2026 · NIST NVD

    Updated

    Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using DefaultHttpHeadersFactory.headersFactory().withValidation(false), then adds user-provided outboundHeaders without any CRLF validation.

Sources

  • CVE.orgVulnerability recordCVE-2026-42578

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-42578

    30-day exploitation probability 1.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-42578

    Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using DefaultHttpHea

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.