Xen Orchestra prior to version 6.9.0 is vulnerable to prototype pollution that allows any authenticated user to execute code as a global administrator. By abusing the unprotected vm.importFromEsxi and vm.importMultipleFromEsxi methods, a malicious user can direct the Xen Orchestra server to load a crafted VMware configuration file containing __proto__.permission, which pollutes Object.prototype and propagates administrative privileges to accounts that normally lack them. This flaw results in a direct escalation of privilege and enables remote code execution on the underlying host.

The affected product is Xen Orchestra, a virtualization management platform developed by vatesfr. Versions earlier than 6.9.0 are impacted and must be updated to the latest release to mitigate the vulnerability.

The CVSS score of 7.7 indicates a high severity for this flaw. Although the EPSS score is not available, the lack of listing in the CISA KEV catalog does not diminish the potential risk to systems that remain in the vulnerable state. The attack requires an authenticated user who can invoke the import methods and must supply a malicious ESXi host that serves a specially crafted .vmx file; once executed, the attacker gains full administrative control and can run arbitrary code.