CVE-2026-70585 in Windows
Summary
by MITRE • 09/09/2026
Use after free in Windows Services for NFS ONCRPC XDR Driver allows an authorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified involves a use-after-free error within the Windows Services for Network File System, specifically affecting the ONC/RPC XDR driver component. This flaw arises from improper memory management practices where the system continues to reference a block of memory after it has been freed and potentially reallocated for other purposes. In the context of network file systems, this driver handles external data representation (XDR) encoding and decoding operations essential for interoperability between different computing environments. When an attacker can trigger specific RPC calls that manipulate these memory structures, they may cause the system to execute arbitrary code using the stale pointer associated with the freed memory region.
This type of vulnerability is classified under CWE-416, which denotes Use After Free conditions. The core technical issue lies in the lifecycle management of dynamic memory allocations within the kernel-mode driver. If the reference count or ownership semantics are not strictly enforced during packet processing, a previously allocated buffer might be released while still being accessed by an ongoing operation. This creates a window where maliciously crafted input can overwrite adjacent heap structures or redirect execution flow to attacker-controlled payloads. The severity of this flaw is amplified because it resides in a privileged component that handles network-facing protocols, making it accessible through local interactions with the NFS service interface.
From an operational perspective, successful exploitation allows an authenticated user on the system to achieve arbitrary code execution within the context of the operating system kernel or high-privilege process. This effectively grants the attacker full control over the affected machine, enabling them to install programs, view, change, or delete data, and create new accounts with unrestricted permissions. The impact extends beyond simple privilege escalation; it compromises the integrity, availability, and confidentiality of the entire host environment. Since Windows Services for NFS is often deployed in enterprise environments integrating heterogeneous systems, a compromise here can serve as a pivot point for lateral movement within the network infrastructure.
The attack vector aligns with MITRE ATT&CK techniques related to local privilege escalation and execution through system services. Specifically, it relates to mechanisms where attackers exploit software vulnerabilities to gain higher-level access without requiring physical interaction or remote network exposure beyond what is already permitted by service configurations. The presence of this vulnerability indicates a need for rigorous code review focusing on pointer validity checks and memory deallocation sequences within the ONC/RPC stack implementation.
Mitigation strategies primarily involve applying vendor-supplied security updates that patch the underlying memory management logic in the XDR driver. Administrators should ensure that all systems running Windows Services for NFS are updated to the latest cumulative patches provided by Microsoft. Additionally, reducing the attack surface involves disabling the feature if it is not actively required for business operations. Network segmentation and strict access controls on RPC endpoints can further limit exposure, ensuring that only trusted hosts can interact with the NFS services. Regular vulnerability scanning focused on kernel-level drivers and monitoring for anomalous process behavior associated with system service execution are recommended defensive measures to detect potential exploitation attempts before they result in full compromise.