LOCKING YOUR SSH-AGENT EXPOSED LOCAL-ONLY KEYS UNTIL OPENSSH 10.5

Summary from the TLDR InfoSec newsletter

OpenSSH 10.5 fixed a flaw introduced in version 10.4 where locking the ssh-agent disabled the check distinguishing local requests from forwarded ones, letting remote connections perform operations meant to stay local, including adding PKCS#11 tokens and bypassing destination-restricted keys, alongside a use-after-free in the ssh client and a broken authorized_keys "restrict" keyword that failed to block tunnel forwarding.