Subject: bug#863: haproxy forward upgrade and connection headers as default (h2c request smuggling)

From: gr0 bUst4 <[email-masked]>
Date: Mon, 28 Oct 2024 10:32:09 +0000

Package: haproxy

Version: 2.6.12-1

suggest to fix this default forwarding

-------- Message transféré --------
Sujet : 	Re: CVE request: headers forward can lead to h2c request 
smuggling (fwd)
Date : 	Mon, 28 Oct 2024 07:08:40 +0100
De : 	Willy TARREAU <[email-masked]>
Pour : 	[email-masked]

Hello,

Thanks for contacting us!

> i did a CVE request about HAProxy and the default forward of the headers
> upgrade and connection which can lead to an h2c request smuggling or a
> web-socket smuggling.
>
> The CVE request is just about h2c (over clear text) i didn't POC 
> enough for
> the web-socket smuggling.
>
> I'll appreciate to talk about this with you.

I guess you're speaking about this commit:

7b89aa5b19 ("BUG/MINOR: h1: do not forward h2c upgrade header token")

If so, it's already backported for next stable releases:
3.0: cba44958ae
2.9: cf31943d74

If not, do not hesitate to share details about your concerns.

Thanks,
Willy