[GHSA] GHSA-j8pm-gj4c-rq4x (high) — league/commonmark: Denial of service via crafted code fences, reference links, and emphasis delimiters

GHSA-j8pm-gj4c-rq4x Severity: high CVE: None

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