open-multi-agent 1.5.0 through 1.21.2 Sandbox Escape via file_write Dangling Symlink

open-multi-agent (@open-multi-agent/core) 1.5.0 through 1.21.2 contains a link following vulnerability in the file_write tool sandbox that allows attackers to create files outside the workspace root by using dangling symlinks. Attackers can plant a dangling symlink in the workspace and steer the agent via prompt injection to write attacker-influenced content anywhere the agent process can write.