CVE-2026-42584

HIGH

Netty: HttpClientCodec response desynchronization

Title source: cna
STIX 2.1

Description

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.

References (1)

Core 1
Core References

Scores

CVSS v3 7.3
EPSS 0.0032
EPSS Percentile 23.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-444
Status published
Products (7)
io.netty/netty-codec-http 0 - 4.1.133.FinalMaven
io.netty/netty-codec-http 4.2.0.Alpha1 - 4.2.13.FinalMaven
io.netty/netty-codec-http < 4.1.133.Final
io.netty/netty-codec-http >= 4.2.0.Alpha1, < 4.2.13.Final
netty/netty < 4.1.133
netty/netty < 4.1.133.Final
netty/netty >= 4.2.0.Alpha1, < 4.2.13.Final
Published May 13, 2026
Tracked Since May 14, 2026