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CVE-2026-59900GHSA-C69G-56F8-XWQJ

Netty codec-http2: Lack of Host Header Deduplication in HTTP/2→HTTP/1.x Translation Leads to Request Routing Bypass

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.2.16.Final, 4.1.136.Final
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, 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. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • netty netty

    From 4.2.0.Final · fixed in 4.2.16.Final; fixed in 4.1.136.Final

  • io.netty:netty-codec-http2Maven

    From 4.2.0.Final · fixed in 4.2.16.Final

  • io.netty:netty-codec-http2Maven

    fixed in 4.1.136.Final

References 3

GitHub · netty/netty