CVE-2026-100659
Netty 4.2.0 through 4.2.17 HTTP/3 Request Routing Bypass
- State
- Published
- Severity
- 6.9 Medium
- Published
- Sep 26, 2026
- Updated
- Sep 28, 2026
- Reserved
- Sep 26, 2026
Description
Netty's HTTP/3 codec (io.netty:netty-codec-http3) in versions 4.2.0.Final through 4.2.17.Final does not enforce the RFC 9114 requirement that the :authority pseudo-header field and a literal host header field, when both present, carry the same value. A remote unauthenticated peer can send a single HEADERS frame containing both fields with differing, attacker-controlled values; the request is accepted and delivered to the application with two conflicting authorities, allowing routing, virtual-host, and access-control decisions to be bypassed when different components in the request path consult different fields. This issue is fixed in 4.2.18.Final.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.9 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 6.5 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N | VulnCheck |
Weaknesses
- CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Affected Products
| Product | Versions |
|---|---|
nettynetty |
|
References
- GitHub Security Advisory (GHSA-q9pg-8h3j-8hvm)vendor-advisory
- VulnCheck Advisory: Netty 4.2.0 through 4.2.18 HTTP/3 Request Routing Bypassthird-party-advisory
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