CVE-2026-93569

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.

  • Published Sep 18, 2026
  • CVSS 8.2 high
  • 1.4% chance of exploitation in the next 30 days (EPSS)
  • A fix is available

Affected software

CVE-2026-93569 at the National Vulnerability Database