PT-2026-63546 · Netty · Netty

CVE-2026-59898

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Published

2026-07-22

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Updated

2026-08-06

CVSS v3.1

7.5

High

VectorAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Name of the Vulnerable Software and Affected Versions Netty versions prior to 4.1.136.Final Netty versions prior to 4.2.16.Final
Description An attacker can force a WebSocket upgrade through the lax V07 or V08 handshaker. By sending the Sec-WebSocket-Version: 7 header and omitting the Connection: Upgrade and Upgrade: websocket headers, a protocol switch is completed. Because a proxy would not recognize this as an Upgrade request, it enables protocol-confusion and HTTP request smuggling attacks.
Recommendations Update to version 4.1.136.Final. Update to version 4.2.16.Final.

Exploit

Fix

HTTP Request/Response Smuggling

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Weakness Enumeration

Related Identifiers

CVE-2026-59898
GHSA-4MP9-239F-G9HG
OPENSUSE-SU-2026:11394-1
SUSE-SU-2026:3482-1

Affected Products

Netty