CVE-2026-42584

EUVD-2026-30127

13.05.2026, 19:17

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpClientCodec pairs each inbound response with an outbound request by queue.poll() once per response, including for 1xx. If the client pipelines GET then HEAD and the server sends 103, then 200 with GET body, then 200 for HEAD, the queue pairs HEAD with the first 200. The HEAD rule then skips reading that message’s body, so the GET entity bytes stay on the stream and the following 200 is parsed from the wrong offset. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

HTTP Request/Response Smuggling

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	7.3 HIGH	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Base Score

CVSS 3.x

EPSS Score

Percentile: 34%

Affected Products (NVD)

Vendor	Product	Version
netty	netty	𝑥 < 4.1.133
netty	netty	4.2.0 ≤ 𝑥 < 4.2.13

𝑥

= Vulnerable software versions

Debian Releases

Debian Product

Codename

netty

bookworm	vulnerable
bookworm (security)	vulnerable
bullseye	vulnerable
bullseye (security)	vulnerable
forky	vulnerable
sid	vulnerable
trixie	vulnerable
trixie (security)	vulnerable

Known Exploits!

Common Weakness Enumeration

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.

Vulnerability Media Exposure

References

https://github.com/netty/netty/security/advisories/GHSA-57rv-r2g8-2cj3