Privilege escalation via replaceable remote proxy script

TOCTOU race in Lapce 0.2.8 allows local users to gain another user's privileges when that user starts an SSH remote session. remote.rs uploads a fixed-name /tmp/lapce-proxy.sh, then changes its permissions and executes it without validating its integrity, allowing replacement between upload and execution. The attacker needs prior access to the remote host, and a more privileged Lapce user must initiate the connection; the supplied proof of concept executes commands with that user's rights.