CVE-2026-100663

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Source
https://cve.org/CVERecord?id=CVE-2026-100663
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-100663.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-100663
Aliases
  • GHSA-jgph-cgq3-c627
Downstream
Published
2026-09-26T13:23:29Z
Modified
2026-09-30T03:30:40Z
Severity
  • 8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N CVSS Calculator
Summary
Netty HTTP/1 CONNECT authority-form mistranslated to malformed HTTP/3
Details

Netty's HTTP/3 codec (io.netty:netty-codec-http3) from 4.2.2.Final through 4.2.17.Final does not special-case HTTP/1 CONNECT authority-form request-targets when converting HTTP/1 messages to HTTP/3 in HttpConversionUtil.toHttp3Headers. The authority-form target (e.g., "CONNECT trusted.example:443") is parsed as a URI, so its host is emitted as :scheme, :path is set to "/", and the HTTP/1 Host header is used as :authority; if no Host header is present the CONNECT target is dropped. In a Netty-based HTTP/1-to-HTTP/3 proxy or gateway, a remote client can send a CONNECT request whose Host header names a different authority than the request-target, producing a malformed HTTP/3 CONNECT whose tunnel :authority is attacker-controlled. This can bypass tunnel allow-lists, egress policy, backend selection, or audit controls that validate the HTTP/1 CONNECT request-target before forwarding over HTTP/3. The issue is fixed in 4.2.18.Final.

Database specific 
{
    "cna_assigner":  "VulnCheck",
    "cwe_ids":  [
        "CWE-20"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100663.json"
}
References

Affected packages

Git / github.com/netty/netty

Affected ranges

Type
GIT
Repo
https://github.com/netty/netty
Events
Introduced
660edeaefad4a4cedbd61584e8f668ad2d89f0b8
Fixed
2521f494432e27415a567d3a81a9eb907abf20b3
Database specific
Show details 
{
    "extracted_events":  [
        {
            "introduced":  "4.2.2.Final"
        },
        {
            "fixed":  "4.2.18.Final"
        },
        {
            "fixed":  "4.2.17.Final"
        }
    ],
    "source":  [
        "AFFECTED_FIELD",
        "DESCRIPTION"
    ]
}

Affected versions

netty-4.*
netty-4.2.10.Final
netty-4.2.11.Final
netty-4.2.12.Final
netty-4.2.13.Final
netty-4.2.14.Final
netty-4.2.15.Final
netty-4.2.16.Final
netty-4.2.17.Final
netty-4.2.2.Final
netty-4.2.3.Final
netty-4.2.4.Final
netty-4.2.5.Final
netty-4.2.6.Final
netty-4.2.7.Final
netty-4.2.8.Final
netty-4.2.9.Final
Other
netty-clang-bin

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-100663.json"