CVE-2026-93567: Io.netty/netty-codec-http2: http/1 authority-form connect is translated to malformed http/2 connect with host-controlled :authority

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-18 · updated 2026-10-19
Weakness: CWE-20

Description

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 products

Red Hat build of Keycloak 26.4: all versions
Red Hat Build of Apache Camel 3.33.3.SP2: all versions — fixed in 4.1.138.Final-redhat-00001
Red Hat build of Apache Camel 4 for Quarkus 3: all versions
Red Hat build of Apache Camel for Spring Boot 4: all versions
Red Hat build of Apicurio Registry 3: all versions
Red Hat Data Grid 8: all versions
Red Hat Fuse 7: all versions
Red Hat JBoss Enterprise Application Platform 7: all versions
Red Hat JBoss Enterprise Application Platform Expansion Pack: all versions
Red Hat Single Sign-On 7: all versions

How to fix

Upgrade to a fixed version: Red Hat Build of Apache Camel 3.33.3.SP2 4.1.138.Final-redhat-00001. Check the vendor advisory for mitigations.

References

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