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No exploitation reportedFix availableAwaiting NVD analysis

CVE-2026-93567

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

No exploitation reported by the sources we read.

  • Published2026-09-18
  • WeaknessCWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2026-09-1814:23CVE publishedCNA

Versions per branch

Products declared by the CNA23 products

As redhat, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

17 more products in the CVE record.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-06

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • elasticsearchCleanStartall versions · fixed in 9.3.5-r6
  • io.netty:netty-codec-http2Echo:Mavenall versions · fixed in 4.1.132.Final+echo.1
  • nettyUbuntu:Pro:26.04:LTSall versions · no fixed version listed
  • nettyUbuntu:Pro:24.04:LTSall versions · no fixed version listed
  • nettyUbuntu:Pro:22.04:LTSall versions · no fixed version listed
  • nettyUbuntu:Pro:20.04:LTSall versions · no fixed version listed
  • nettyUbuntu:Pro:18.04:LTSall versions · no fixed version listed
  • nettyUbuntu:Pro:16.04:LTSall versions · no fixed version listed

21 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-93567 Red Hat Product Security25 products fixed · 8 known affected

    io.netty/netty-codec-http2: HTTP/1 authority-form CONNECT is translated to malformed HTTP/2 CONNECT with Host-controlled :authority

    netty-codec-http2 as a component of Red Hat build of Apache Camel 4 for Quarkus 3 · netty-codec-http2 as a component of Red Hat build of Apache Camel for Spring Boot 4 · netty-codec-http2 as a component of Red Hat build of Apicurio Registry 3 · +5 more

  • RHSA-2026:95760 Red Hat Product Security9 products fixed

    Red Hat Security Advisory: Red Hat build of Keycloak 26.4.17 Images Security Update

  • RHSA-2026:95759 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat build of Keycloak 26.4.17 Security Update

  • RHSA-2026:95221 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 8.1.9 XP 6.0.7.GA release

  • RHSA-2026:83612 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat build of Debezium 3.6.3 release

  • RHSA-2026:70257 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Build of Apache Camel 4.18 for Quarkus 3.33 update is now available (RHBQ 3.33.3.SP2)

2 more advisories

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2026:95760 · 9 productsBefore applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on.
  2. Vendor fix Red Hat Product Security RHSA-2026:95221 · 1 productBefore applying the update, make sure all previously released errata relevant to your system have been applied. Also, back up your existing installation, including all applications, configuration files, databases and database settings. For details on how to apply this update, refer to: https://acce…
  3. Vendor fix Red Hat Product Security RHSA-2026:83612 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  4. Vendor fix Red Hat Product Security RHSA-2026:70257 · 1 productBefore applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on. The References section of this erratum contains a download link (you must log in to download the update).
  5. Workaround from the vendor Red Hat Product Security RHSA-2026:95760 · 9 productsSee https://github.com/netty/netty/security/advisories/GHSA-45h4-vhwh-fmhg for fixed versions and remediation guidance.

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Published
2026-09-18
Last Modified
2026-11-06
NVD status
Awaiting Analysis
GitHub Advisory
GHSA-xf8w-rc87-x5gw

Frequently asked questions

What is CVE-2026-93567?

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.

Is CVE-2026-93567 actively exploited?

Active exploitation of CVE-2026-93567 has not been confirmed. Its EPSS score was 2.9% on 2026-11-12, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-93567?

CVE-2026-93567 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

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