ssh_dispatch_run_fatal: incorrect signature with mlkem768x25519-sha256

[Sam James]

Christian Kujau <mindrot at nerdbynature.de> writes:

> Hello list,
>
> I have this PowerBook G4 with OpenBSD 7.6 (macppc, OpenSSH_9.9, LibreSSL 
> 4.0.0) installed but haven't used it in a while. Switched it on and wanted 
> to SSH from my Macbook (M2, with macOS 26 installed, OpenSSH_10.0p2, 
> LibreSSL 3.3.6) to the Powerbook but:
>
>  $ ssh 192.168.178.62
>  ssh_dispatch_run_fatal: Connection to 192.168.178.62 port 22: incorrect signature

Might be a miscompilation like
https://github.com/llvm/llvm-project/issues/163053 was (of course not
exactly the same). Does it happen if you use ./configure
--without-hardening?

> [...]

sam