libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_GetBuffer, XML_Parse, XML_ParseBuffer, XML_ParserFree, or XML_ParserReset from within handlers in cases of a policy violation. Thus, a use-after-free can occur,

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Use After Free

libexpat.so is vulnerable to use-after-free. The vulnerability exists due to a lack of entity value validations in the XMLParserFree parameter of the parserCreate function in xmlparse.c. An attacker could exploit it to lead to memory consumption resulting in an application crash...