CVE-2026-93567
Published:September 18, 2026
Updated:October 09, 2026
A flaw was found in Netty's HTTP/2 codec. When converting HTTP/1 CONNECT requests to HTTP/2, the component incorrectly uses the Host header instead of the CONNECT authority-form request-target for the tunnel authority. A remote attacker can exploit this by supplying a different Host header, leading to a malformed HTTP/2 CONNECT request. This can bypass security controls such as tunnel allow-lists or egress policies, resulting in integrity loss.
Affected Packages
https://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.2.0.Final <netty-4.2.18.FinalFix Suggestion:
Update to version netty-4.2.18.Finalhttps://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.1.0.Final <netty-4.1.138.FinalFix Suggestion:
Update to version netty-4.1.138.Finalio.netty:netty-all (JAVA):
Affected version(s) >=4.1.0.Beta5 <4.1.138.FinalFix Suggestion:
Update to version 4.1.138.Finalio.netty:netty-codec-http2 (JAVA):
Affected version(s) >=4.1.0.Final <4.1.138.FinalFix Suggestion:
Update to version 4.1.138.Finalio.netty:netty-codec-http2 (JAVA):
Affected version(s) >=4.2.0.Final <4.2.18.FinalFix Suggestion:
Update to version 4.2.18.FinalRelated Resources (6)
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Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Improper Input Validation
EPSS
Base Score:
1.52