shell-quote's "quote()" function did not validate object-token inputs against the operator model used by "parse()". The ".op" field was backslash-escaped character by character using "/(.)/g", which in JavaScript does not match line terminators (\n, \r, U+2028, U+2029). A line terminator in ".op" therefore passed through unescaped into the output; POSIX shells treat a literal newline as a command separator, so any content after it would execute as a second command. The vulnerable code path is reachable in two ways: (1) direct construction of "{ op: '...\n...' }" from external input, and (2) via "parse(cmd, envFn)" when "envFn" returns object tokens whose ".op" is attacker-influenced. Both are documented API surface. Fixed by replacing the per-character escape with strict shape validation: ".op" must match the parser's control-operator allowlist; "{ op: 'glob', pattern }" validates "pattern" and forbids line terminators; "{ comment }" validates "comment" and forbids line terminators; any other object shape throws "TypeError".