Marked is a markdown parser and compiler. From 18.0.0 to 18.0.1, a critical Denial of Service (DoS) vulnerability exists in marked. By providing a specific 3-byte input sequence a tab, a vertical tab, and a newline (\x09\x0b\n)—an unauthenticated attacker can trigger an infinite recursion loop during parsing. This leads to unbounded memory allocation, causing the host Node.js application to crash via Memory Exhaustion (OOM). This vulnerability is fixed in 18.0.2.