openssh unix dev - Oct 2025 - openssh.com/pq.html: warning even without explicit kex config?

What is the exact warning you?re getting?

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________________________________
From: openssh-unix-dev <openssh-unix-dev-bounces+scott.fields=kyndryl.com at
mindrot.org> on behalf of Steffen Nurpmeso <steffen at sdaoden.eu>
Sent: Saturday, October 11, 2025 1:28:34 PM
To: openssh-unix-dev at mindrot.org <openssh-unix-dev at mindrot.org>
Subject: [EXTERNAL] openssh.com/pq.html: warning even without explicit kex
config?

Hello.

May i dare to ask, i get that warning now that i have updated my
local OpenSSH; i have restarted the local sshd; the server is
AlpineLinux edge, sshd restarted, so both ends run 10.2p1 aka
10.2_p1.  I have no explicit kex configuration, however
HostKeyAlgorithms is ssh-ed25519 (only these pri/pub keys exist).
Why do i get the warning, i thought it is about KexAlgorithms?
The output of "$ ssh -Q kex" is identical.

--steffen
|
|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)
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On 2025/10/11 19:19, SCOTT FIELDS via openssh-unix-dev
wrote:
> What is the exact warning you?re getting?
the only warning which refers to pq.html is this one

static void
warn_nonpq_kex(void)
{
	logit("** WARNING: connection is not using a post-quantum key exchange
algorithm.");
	logit("** This session may be vulnerable to \"store now, decrypt
later\" attacks.");
	logit("** The server may need to be upgraded. See
https://openssh.com/pq.html");
}

the warning is currently disabled if you set KexAlgorithms in config
to anything other than the default, or if you set WarnWeakCrypto to
'no' or 'no-pq-kex'.