CVE-2026-50020
Description
Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, before reading the first request-line, `HttpObjectDecoder` skips every byte for which `Character.isISOControl(b)` is `true` (0x00–0x1F and 0x7F) as well as all whitespace. RFC 9112 §2.2 only asks servers to ignore empty CRLF lines preceding the request-line — a carefully scoped robustness allowance intended to handle HTTP/1.0 POST workarounds. Silently absorbing NUL bytes, SOH, STX, and other non-CRLF control characters goes significantly beyond this, and can be exploited for request-boundary confusion in pipelined or multiplexed transports where a front-end component treats those bytes differently. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
How to fix
- netty netty4.1.135, 4.2.15 or later
- io.netty:netty-codec-http4.2.15.Final, 4.1.135.Final or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| netty netty | v < 4.1.135, 4.2.0 ≤ v < 4.2.15 | 4.1.135, 4.2.15 |
| io.netty:netty-codec-httpMaven | 4.2.0.Final ≤ v < 4.2.15.Final, v < 4.1.135.Final | 4.2.15.Final, 4.1.135.Final |
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Attack Surface Management
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