GHSA-J8PM-GJ4C-RQ4X league/commonmark: Denial of service via crafted code fences, reference links, and emphasis delimiters

Impact Affected versions of league/commonmark perform super-linear work on three independent parsing paths, all of which are reachable on a stock new CommonMarkConverter with default configuration and no extensions registered. Each trigger fits on a single line of input, so no complex Markdown...