AIKIDO-2026-931565
hyper is vulnerable to HTTP Request Smuggling
54
Medium Risk
This Affects:
hyperTL;DR
hyper's HTTP/1 server parser keeps a Content-Length header on a request that also carries Transfer-Encoding whenever the Content-Length field appears first on the wire, and it leaves the connection open after responding. When hyper is used as an intermediary and forwards such a request, a downstream recipient that trusts the stale Content-Length can disagree on where the message body ends. This mismatch enables request smuggling or response splitting against the downstream. The fix discards the overridden Content-Length header and closes the connection as required by RFC 9112.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and are using hyper as an HTTP/1 server that forwards requests to a downstream recipient.
Background info
hyper is vulnerable to HTTP Request Smuggling in versions 1.0.0 - 1.10.1.
How to fix this
Upgrade the hyper library to the patch version.
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SOC 2Compliant
ISO 27001Compliant