CVE-2023-28631: Comrak AST node data is not validated (GHSL-2023-049)

Impact

A Comrak AST can be constructed manually by a program instead of parsing a Markdown document with parse_document. This AST can then be converted to HTML via html::format_document_with_plugins. However, the HTML formatting code assumes that the AST is well-formed. For example, many AST notes contain [u8] fields which the formatting code assumes is valid UTF-8 data. Several bugs can be triggered if this is not the case.

Patches

0.17.0 contains adjustments to the AST, storing strings instead of unvalidated byte arrays.

Workarounds

• Validate UTF-8 correctness of all data when assigning to &[u8] and Vec<u8> fields in the AST.

References

n/a