Mistune toc / TableOfContents directive: heading IDs use predictable `toc_N` numbering with no slugification, allowing collision with attacker-controlled `id="toc_N"` content

Summary Type: Predictable identifier generation. The toc plugin and TableOfContents directive both default to generating heading IDs of the form toc1, toc2, toc3, ... with no input-derived component. An attacker who can place a heading anywhere in the document can predict which tocN ID it will...