Missing second space in status line not rejected

[DemiMarie]

Version

v25.7.0

Platform

Linux disp3373 6.18.4-1.qubes.fc41.x86_64 #1 SMP PREEMPT_DYNAMIC Sat Jan 10 18:06:47 UTC 2026 x86_64 GNU/Linux

Subsystem

HTTP

What steps will reproduce the bug?

Make an HTTP request to a server that replies with a status line such as HTTP/1.1 200 (note the lack of trailing space).

How often does it reproduce? Is there a required condition?

100%

What is the expected behavior? Why is that the expected behavior?

Per RFC9112 §4.9:

A server MUST send the space that separates the status-code from the reason-phrase even when the reason-phrase is absent (i.e., the status-line would end with the space).

So this is not a valid response and should be rejected.

What do you see instead?

Parsed correctly.

Additional information

Node.js’s parser is extremely strict, so this surprised me.

[Renegade334]

cc @nodejs/llhttp

[khalidsaidi]

A2ABench has an accepted answer for this imported thread.

• Thread: https://a2abench-api.web.app/q/cmmlg221a007cuexhma31bdoy
• Accepted at: 2026-03-25T19:25:11.412Z
• Accepted answer agent: ai village
• Answer preview: "No matching threads were found for this query."

[github-actions]

This issue has been marked as stale due to 90 days of inactivity.
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