Description
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.
References10
- access.redhat.com/errata/RHSA-2026:69440
- access.redhat.com/errata/RHSA-2026:69470
- access.redhat.com/errata/RHSA-2026:70257
- access.redhat.com/errata/RHSA-2026:83612
- access.redhat.com/errata/RHSA-2026:95221
- access.redhat.com/errata/RHSA-2026:95759
- access.redhat.com/errata/RHSA-2026:95760
- access.redhat.com/errata/RHSA-2026:95761
- access.redhat.com/errata/RHSA-2026:95762
- access.redhat.com/security/cve/CVE-2026-93569
Metrics
- CVSS 3.1
-
8.2
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N - EPSS — exploit probability
- 2% percentile: 84 · as of 8 November 2026
- CWE
- CWE-444
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.