GHSA-wfpw-mmfh-qq69: Nokogiri: Possible Use-After-Free in XInclude Processing

XInclude substitution performed by Nokogiri::XML::Node#do_xinclude replaced each <xi:include> in place, freeing the include node along with its children (such as <xi:fallback> and its descendants) and any namespaces declared on them. If an application had already exposed one of those nodes or namespaces to Ruby, the corresponding Ruby object was left pointing at freed memory. Using the object could result in invalid reads or writes to memory.

Nokogiri 1.19.4 substitutes each <xi:include> on a defensive copy by default, so the structures libxml2 frees are never the ones bound to live Ruby objects.

Only the CRuby implementation is affected; JRuby is not affected.