CVE-2026-50020
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.
Does this matter?
Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- EPSS
- 0.23% probability · 14th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-444
- Affected
- netty/netty
- Source
- security-advisories@github.com
References
- https://github.com/netty/netty/releases/tag/netty-4.1.135.FinalRelease Notes
- https://github.com/netty/netty/releases/tag/netty-4.2.15.FinalRelease Notes
- https://github.com/netty/netty/security/advisories/GHSA-hvcg-qmg6-jm4cVendor Advisory
- https://github.com/netty/netty/security/advisories/GHSA-hvcg-qmg6-jm4cVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.