GitHub Advisoryadvisory · Maven

GHSA-c69g-56f8-xwqj Netty: [codec-http2] Lack of Host Header Deduplication in HTTP/2→HTTP/1.x Translation Leads to Request Routing Bypass

MEDIUM Published 2026-07-22 Modified 2026-07-22 Official page ↗
Aliases
CVE-2026-59900
Ecosystem
Maven
Packages
io.netty:netty-codec-http2
Severity
Moderate
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Weaknesses
CWE-444
Reviewed
2026-07-22

Affected packages

• Maven io.netty:netty-codec-http2: >= 4.2.0.Final, < 4.2.16.Final → fixed in 4.2.16.Final • Maven io.netty:netty-codec-http2: < 4.1.136.Final → fixed in 4.1.136.Final

Description

Netty's HTTP/2-to-HTTP/1.x translation layer (`Http2StreamFrameToHttpObjectCodec` and `InboundHttp2ToHttpAdapter`) fails to deduplicate or validate `Host` headers when an HTTP/2 client supplies both the `:authority` pseudo-header and a literal `host` header in a single HEADERS frame. The translator maps `:authority` to `Host` and separately copies the literal `host` header, producing an `HttpRequest` object containing two `Host` headers with attacker-controlled differing values.

Related

Alias · CVE (1)

  • CVE-2026-59900 Netty is an asynchronous, event-driven network application framework. vulnerability

Weakness · CWE (1)

  • CWE-444 Inconsistent Interpretation of HTTP Requests weakness

References