Windows RPC and Service Flaws Enabled Privilege Escalation and Sandbox Escape

Multiple public write-ups detailed how Windows service and RPC design flaws enabled local privilege escalation, sandbox escape, and in some cases reliable code execution. Research on the Windows SSDP service linked FC_BINDING_CONTEXT misuse to CVE-2025-48815, showing that a context handle from one RPC interface could be passed into another interface expecting a different type and ultimately abused to call CloseHandle on an unintended handle. Separate analysis of the Windows telephony service described CVE-2024-26230 as a use-after-free in tapisrv caused by improper ownership validation of RPC-managed objects, allowing a dangling pointer to be reclaimed with attacker-controlled data and steered toward LoadLibraryW despite XFG protections. Earlier Windows RPC research also covered Storage Service bugs CVE-2019-0983 and CVE-2019-0998, where file-copy, directory, and ACL logic exposed through RPC could be abused to overwrite privileged files or alter their security descriptors.

Other disclosures showed the same pattern across Windows subsystems. Analysis of CVE-2022-22715 in npfs.sys demonstrated that malformed LOCAL\ named pipe paths could trigger integer overflow and out-of-bounds kernel writes, enabling escape from the Adobe Reader AppContainer sandbox and escalation to kernel read/write. Research into CVE-2021-1648 in splwow64 described bypasses in printer-handle validation and an arbitrary address read, while older work on CVE-2018-8550 examined COM DfMarshal abuse for elevation of privilege through privileged unmarshaling paths. Related reporting also highlighted Microsoft hard-link mitigations and a Citrix restricted-desktop breakout that relied on allowed scripting components rather than a zero-day, underscoring how weak validation, unsafe object handling, and incomplete execution controls repeatedly exposed high-impact privilege boundaries on Windows.