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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-42578

33
FAUCET Score

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.

First published: May 13, 2026Last modified: May 13, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 4.1.133CPE matchmatch criteria
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
>= 4.2.0, < 4.2.13CPE matchmatch criteria
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 4.0

2.9LOW

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
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
NONE
VS Integrity
LOW
VS Availability
NONE
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
PROOF_OF_CONCEPT
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.95%
Probability of exploitation in next 30 days
EPSS Percentile
57.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0095 is in the 32nd percentile among its peer group of 51,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (10)

mavenpatch availablevia ghsa
Product: io.netty:netty-handler-proxyFixed in: 4.1.133.Final
mavenpatch availablevia ghsa
Product: io.netty:netty-handler-proxyFixed in: 4.2.13.Final
ubuntupatch availablevia ubuntu_usn
Product: netty (bionic)Fixed in: 1:4.1.7-4ubuntu0.1+esm6
ubuntupatch availablevia ubuntu_usn
Product: netty (focal)Fixed in: 1:4.1.45-1ubuntu0.1~esm6
ubuntupatch availablevia ubuntu_usn
Product: netty (jammy)Fixed in: 1:4.1.48-4+deb11u2ubuntu0.1+esm3
ubuntupatch availablevia ubuntu_usn
Product: netty (noble)Fixed in: 1:4.1.48-9ubuntu0.1+esm3
ubuntupatch availablevia ubuntu_usn
Product: netty (resolute)Fixed in: 1:4.1.48-16ubuntu0.1~esm2
ubuntupatch availablevia ubuntu_usn
Product: netty (trusty)Fixed in: 1:3.2.6.Final-2+deb8u2ubuntu0.1~esm1
ubuntupatch availablevia ubuntu_usn
Product: netty (xenial)Fixed in: 1:4.0.34-1ubuntu0.1~esm4
github_advisoryworkaround availablevia nvd_reference
View patch

Vendor Advisories (2)

ubuntuUSN-8401-1

Netty vulnerabilities

Jun 8, 2026
mavenGHSA-45q3-82m4-75jrlow

Netty has HTTP Header Injection via HttpProxyHandler Disabled Validation (Incomplete Fix CVE-2025-67735)

May 7, 2026

References

access.redhat.com / errata/RHSA-2026:23808
access.redhat.com / errata/RHSA-2026:24502
access.redhat.com / errata/RHSA-2026:25123
access.redhat.com / errata/RHSA-2026:28010
access.redhat.com / errata/RHSA-2026:36820
access.redhat.com / errata/RHSA-2026:37390
access.redhat.com / errata/RHSA-2026:42644
access.redhat.com / security/cve/CVE-2026-42578
bugzilla.redhat.com / show_bug.cgi
security.access.redhat.com / data/csaf/v2/vex/2026/cve-2026-42578.json
github.com / netty/netty/security/advisories/GHSA-45q3-82m4-75jr
ExploitMitigationVendor Advisory