CVE-2026-93569

Summary

A flaw was found in Netty. A remote unauthenticated attacker can exploit a vulnerability in Netty's HTTP/1 to HTTP/2 conversion process. When an HTTP/1 request includes both an absolute-form request-target and a conflicting Host header, Netty incorrectly prioritizes the Host header for the HTTP/2 :authority field, discarding the original request-target authority. This inconsistency can allow an attacker to bypass security controls in Netty-based proxies or gateways, potentially leading to unauthorized access, cache poisoning, or misrouting of requests.

Affected Software

VendorProductVersion RangeStatus

Weaknesses

  • CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Workarounds

See https://github.com/netty/netty/security/advisories/GHSA-cg2g-fxr4-mg8m for fixed versions and remediation guidance.

References