Advisory severityMedium5.3Red Hat Linux

Medium [CVE-2026-59898] Protocol version confusion in netty-codec-http (WebSocket)

This medium-severity Red Hat Linux advisory covers CVE-2026-59898 affecting Red Hat build of Quarkus 3.27.4.SP3, Red Hat build of Quarkus 3.33.2.SP3, Cryostat 4.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-59898 Source published Jul 9, 2026Source updated Jul 9, 2026

VulniPulse record published Jul 28, 2026Record updated Jul 30, 2026

CVE-2026-59898

Affected products & platforms

Red Hat LinuxUnclassified

Open source advisory

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Summary

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.

A flaw was found in netty-codec-http. The WebSocket handshaker in this component fails to properly validate protocol version information during the WebSocket upgrade process.

A remote attacker can exploit this vulnerability by manipulating the WebSocket handshake, leading to a bypass of security checks or the negotiation of unexpected protocol versions. This could potentially enable protocol-level attacks.

Red Hat severity: Moderate — CVSS 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N). Weakness: CWE-358.

Affected products named by the advisory: Red Hat build of Quarkus 3.27.4.SP3; Red Hat build of Quarkus 3.33.2.SP3; Cryostat 4; OpenShift Serverless; and 19 more.

Affected versions

< 4.1.136.Final
< 4.2.16.Final

Official advisory · high-confidence parse· fetched 13 days ago·verify at source

Fixed versions

4.1.136
4.2.16
netty-codec-http
RHSA-2026:47189
RHSA-2026:47172

Official advisory · high-confidence parse· fetched 13 days ago·verify at source

Mitigation checklist

Recommended fix / mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Official advisory · high-confidence parse· fetched 13 days ago·verify at source

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