Unpatched PhantomRPC Flaw in Windows Enables Privilege Escalation
In April 2026, Kaspersky researchers disclosed 'PhantomRPC,' an unpatched vulnerability in Windows' Remote Procedure Call (RPC) mechanism. This flaw allows attackers with limited local access to deploy malicious RPC servers that impersonate legitimate Windows services. When higher-privileged processes connect to these rogue servers, attackers can escalate their privileges to SYSTEM or administrator levels. The vulnerability arises from how RPC handles connections to unavailable services, permitting any process to register an RPC server on the same endpoint as a legitimate service that is not running. Despite the severity, Microsoft has classified the issue as 'moderate' and has not issued a patch or CVE identifier. ([darkreading.com](https://www.darkreading.com/vulnerabilities-threats/unpatched-phantomrpc-flaw-windows-privilege-escalation?utm_source=openai)) The disclosure of PhantomRPC underscores the persistent risks associated with architectural vulnerabilities in widely used operating systems. Organizations must proactively implement monitoring and privilege management strategies to mitigate potential exploitation, especially in the absence of official patches.
Kill Chain









