# CVE-2026-93569: Io.netty/netty-codec-http2: http/1 absolute-form host mismatch is translated to http/2 :authority, overriding the request-target authority

Status: published. Published: 2026-09-18. Updated: 2026-11-02.

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.

## Remediation

- workaround: See https://github.com/netty/netty/security/advisories/GHSA-cg2g-fxr4-mg8m for fixed versions and remediation guidance. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Build of Apache Camel 3.33.3.SP2 (io.netty/netty-codec-http2): ≥ 4.1.138.Final-redhat-00001; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Build of Debezium 3.6 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat build of Quarkus 3.27.5.SP2 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat build of Quarkus 3.33.3.SP2 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat AMQ Broker 7 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat build of Apache Camel 4 for Quarkus 3 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat build of Apache Camel for Spring Boot 4 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat build of Apicurio Registry 3 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Build of Keycloak (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Data Grid 8 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Fuse 7 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat JBoss Enterprise Application Platform 7 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat JBoss Enterprise Application Platform 8 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat JBoss Enterprise Application Platform Expansion Pack (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Single Sign-On 7 (netty-codec-http2): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 8.2 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 2.19% as of 2026-11-02; percentile 82.45%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-444

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2026:69440 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:69470 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:70257 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:83612 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-93569 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2536962 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-93569; retrieved 2026-11-02; source updated 2026-11-02

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-93569; retrieved 2026-11-02; source updated Not reported

Revision: 081ec09d99c5f59013506253720a74a8e5e6278887e6724fb496c83045ebea95

Canonical: https://y2.dev/cve/CVE-2026-93569

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