StringEqual in TiXmlDeclaration::Parse in tinyxmlparser.cpp in TinyXML through 2.6.2 has a reachable assertion (and application exit) via a crafted XML document with a '\0' located after whitespace.
https://www.forescout.com/resources/sierra21-vulnerabilities
https://sourceforge.net/p/tinyxml/git/ci/master/tree/tinyxmlparser.cpp
https://lists.debian.org/debian-lts-announce/2023/12/msg00024.html