Prior to versions 4.1.136.Final and 4.2.16.Final, Netty's HTTP/2-to-HTTP/1.x translation layer (Http2StreamFrameToHttpObjectCodec and… (CVE-2026-59900)
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.
Prior to versions 4.1.136.Final and 4.2.16.Final, Netty's HTTP/2-to-HTTP/1.x translation layer (Http2StreamFrameToHttpObjectCodec and… (CVE-2026-59900)
Description
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.
CVSS v3.1
Score 5.3medium
Affected software
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Weaknesses
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-c69g-56f8-xwqj
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-59900"]
- Ecosystems
- ["Maven"]
- Database Specific Severity
- MODERATE
- Cvss Version
- 4.0
Threat ID: 6a6150d39c2644c7f8da06de
Added to database: 07/22/2026, 23:22:59 UTC
Last enriched: 08/01/2026, 00:20:16 UTC
Last updated: 09/04/2026, 22:52:13 UTC
Views: 68
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