A recently discovered weakness in Windows Remote Procedure Call (RPC) has been deemed not worthy of a patch by Microsoft, sparking debate over whether it is a feature or a bug. The vulnerability, known as PhantomRPC, allows a process with impersonation rights to escalate to SYSTEM level by impersonating high-privileged clients that connect to a fake RPC server. A researcher has outlined five potential exploitation paths, including coercion and user interaction, highlighting the potential risks associated with this weakness1. The fact that Microsoft does not consider PhantomRPC a vulnerability raises questions about the company's stance on security. The implications of this decision are significant, as it may leave systems vulnerable to exploitation. This development matters to security practitioners because it highlights the need to assess the relevance of Microsoft's security decisions to their own environments and consider additional measures to mitigate potential risks.
Microsoft won’t patch PhantomRPC: Feature or bug?
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Why This Matters
Security developments involving Microsoft add to the evolving threat landscape — assess relevance to your environment.
References
- Malwarebytes Labs. (2026, April 29). Microsoft won’t patch PhantomRPC: Feature or bug? Malwarebytes. https://www.malwarebytes.com/blog/news/2026/04/microsoft-wont-patch-phantomrpc-feature-or-bug
Original Source
Malwarebytes Labs
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