In xinclude in libxml2 before 2.15.4, xmlXIncludeProcess and xmlXIncludeProcessTree do not propagate parseFlags. This has security relevance for, for example, the XML_PARSE_NONET flag, if (without it) a custom resource loader accesses the internet and triggers XML external entity injection, SSRF, or a denial of service (e.g., for an attacker-controlled internet resource that is intentionally slow).
https://github.com/GNOME/libxml2/compare/v2.15.3...v2.15.4
https://github.com/GNOME/libxml2/commit/b63cd517afecb76582dd9488c55e54ceaf50de61