libxslt: Use-After-Free in libxslt numbers.c

numbers.c in libxslt before 1.1.43 has a use-after-free because, in nested XPath evaluations, an XPath context node can be modified but never restored. This is related to xsltNumberFormatGetValue, xsltEvalXPathPredicate, xsltEvalXPathStringNs, and xsltComputeSortResultInternal.

A flaw was found in libxslt numbers.c. This vulnerability allows a use-after-free, potentially leading to memory corruption or code execution via nested XPath evaluations where an XPath context node can be modified but not restored.