Validate oval.xml hangs

[swyan]

When I run:

python3 ./validate_oval_definitons_files.py ./oval.xml

where the oval.xml is downloaded from https://oval.cisecurity.org/repository/download/5.11/compliance, 5.11.1 (non zipped version), it either hangs:

python3 ./validate_oval_definitons_files.py /home/fsadmin/OVALRepo/oval.xml
INFO: Preparing to validate 1 file(s)
INFO: 1. /home/fsadmin/OVALRepo/oval.xml
INFO: Performing schema validation
(no more logs on the terminal)

or throws errors:

Traceback (most recent call last):
File "src/lxml/xmlerror.pxi", line 94, in lxml.etree._LogEntry._setError
MemoryError
Exception ignored in: 'lxml.etree._BaseErrorLog._receive'
Traceback (most recent call last):
File "src/lxml/xmlerror.pxi", line 94, in lxml.etree._LogEntry._setError
MemoryError
Traceback (most recent call last):
File "./validate_oval_definitons_files.py", line 75, in
main()
File "./validate_oval_definitons_files.py", line 42, in main
lib_xml.schema_validate(filepath, schema_path)
File "/home/fsadmin/OVALRepo/scripts/lib_xml.py", line 161, in schema_validate
xml = etree.parse(xml)
File "src/lxml/etree.pyx", line 3426, in lxml.etree.parse
File "src/lxml/parser.pxi", line 1839, in lxml.etree._parseDocument
File "src/lxml/parser.pxi", line 1865, in lxml.etree._parseDocumentFromURL
File "src/lxml/parser.pxi", line 1769, in lxml.etree._parseDocFromFile
File "src/lxml/parser.pxi", line 1162, in lxml.etree._BaseParser._parseDocFromFile
File "src/lxml/parser.pxi", line 600, in lxml.etree._ParserContext._handleParseResultDoc
File "src/lxml/parser.pxi", line 710, in lxml.etree._handleParseResult
File "src/lxml/parser.pxi", line 639, in lxml.etree._raiseParseError
File "../../oval.xml", line 2200045
lxml.etree.XMLSyntaxError: Extra content at the end of the document, line 2200045, column 53