AIKIDO-2026-319775

TL;DR

The parser performs linear work on three paths that are reachable with default configuration: fenced code block detection, shortcut and collapsed reference link label lookup, and emphasis, strikethrough, and highlight delimiter processing. Each trigger fits on a single line, so crafted Markdown forces catastrophic regex backtracking, repeated normalization of long labels, or an unbounded delimiter cache key space. Converting a small crafted input can exhaust available workers so legitimate requests fail. The fix makes the fence quantifier possessive, applies the reference label length limit before normalization, and clamps delimiter cache keys to a bounded bucket.