HTTP/1 server connection desynchronization after 2xx CONNECT response in net/http
At a glance
Severity
HIGH 7.5
EPSS
EPSS 0.41 % · percentile 36 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
Go
NVD status
Awaiting Analysis
Description
When an HTTP server handler sends a 2xx response to an HTTP/1 CONNECT request and returns without hijacking the connection, the server improperly continues to read and serve requests from the connection. Since a 2xx response to an HTTP/1 CONNECT converts the connection into a tunnel, the server should not treat the connection as continuing to contain HTTP. The impact of this misbehavior is mostly limited to potential request smuggling, where an intermediate proxy considers the data on the connection to be tunneled and the server considers it to be HTTP.
