Description

Use after free in Windows Work Folder Service allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:18:09.447Z",
  "pubdate": "2026-08-11T17:18:09.447Z",
  "executiveSummary": "A use-after-free vulnerability exists within the Windows Work Folder Service, specifically affecting local privilege management. This security flaw enables an authorized local attacker to manipulate memory management inadequacies to achieve local privilege escalation on targeted systems.\nThe vulnerability directly impacts the Windows Work Folder Service component across applicable Microsoft Windows operating systems. The risk implication is severe because it allows a low-privileged local user to execute arbitrary code or commands in the context of a higher-privileged account, undermining the host operating system's security boundaries.\nExploitation requirements dictate that the attacker must already possess local access and authorization to interact with the vulnerable service. The attacker capabilities include leveraging the use-after-free condition during object lifecycle management to corrupt heap memory and hijack control flow. Since exploitation is localized, network exposure is not a prerequisite, but the attack vector relies heavily on precise timing and local interaction with the Windows Work Folder Service API or inter-process communication mechanisms.",
  "technicalDetails": "The vulnerability is rooted in a memory management flaw, specifically a use-after-free condition, residing within the Windows Work Folder Service. A use-after-free occurs when the application continues to use a pointer after the memory object it references has been deallocated or freed. This typically happens due to improper reference counting, asynchronous operation handling, or flawed state machine logic during service execution.\nThe vulnerable component is the internal state handling and object management subsystem of the Windows Work Folder Service. Affected versions include the default implementations packaged within vulnerable iterations of the Windows operating system where the service is active. The attack requires local authentication and specific privilege requirements, meaning the threat actor must execute code locally on the target machine under a standard user context before attempting exploitation.\nThe step-by-step attack flow proceeds as follows: First, the local attacker interacts with the Windows Work Folder Service, initiating sequences that allocate specific objects in heap memory. Second, the attacker triggers conditions—such as forcing specific error states, race conditions, or termination routines—that cause the service to prematurely free the target memory object while retaining a dangling pointer to that memory address. Third, the attacker performs heap feng shui or memory grooming to re-allocate the newly freed memory chunk with controlled malicious payload data.\nWhen the Windows Work Folder Service subsequently attempts to access the dangling pointer, it interacts with the attacker-controlled data as if it were the original legitimate object. This leads to improper function pointer dereferencing or execution of forged virtual method tables. Consequently, the payload behavior dictates that control flow is redirected to malicious shellcode or routines supplied by the attacker.\nThe post-exploitation impact of this vulnerability is significant local privilege escalation. By successfully hijacking the execution flow of the Windows Work Folder Service, which often operates with elevated system or administrative privileges, the attacker can execute arbitrary commands with those same elevated credentials. This grants the attacker full control over the affected operating system, facilitating persistence, credential dumping, and lateral movement."
}