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CVE-2026-59898

Netty: WebSockets V07/V08 handshaker missing Connection/Upgrade validation

Published: Jul 29, 2026Updated: Aug 6, 2026 Sources: CVE List NVDCWE-444
7.5HIGH
NVD MITRE
EPSS Score
0.2%
Top 83.7%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

Description

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, ab attacker can force WebSocket upgrade via the lax V07 (or V08) handshaker by sending `Sec-WebSocket-Version: 7` and omitting `Connection: Upgrade` / `Upgrade: websocket` headers, completing a protocol switch that a proxy would not recognize as an Upgrade request and enabling HTTP request smuggling / protocol-confusion attacks. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-444

Affected Products

netty
oss-projectaka io.netty:netty, netty-incubator-codec-ohttp
nettyLibraryLibrary
OSS Libraries / generic-library

Exploitability

Official Patch Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Collection
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References

https://github.com/netty/netty/security/advisories/GHSA-4mp9-239f-g9hg
github.com
https://github.com/netty/netty/releases/tag/netty-4.1.136.Final
github.com
https://github.com/netty/netty/releases/tag/netty-4.2.16.Final
github.com

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