Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Backup Engine allows an authorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.0",
  "pubDate": "2026-08-11T17:18:44.630Z",
  "pubdate": "2026-08-11T17:18:44.630Z",
  "executiveSummary": "This vulnerability is classified as a concurrent execution using shared resource with improper synchronization, commonly known as a race condition, residing within the Windows Backup Engine. The flaw allows an authorized local attacker to successfully elevate privileges on vulnerable systems. The primary impact of this security deficiency is unauthorized privilege escalation, enabling a local user to execute code or perform administrative actions beyond their intended security context. The affected system is the Windows Backup Engine. The risk implications are severe for multi-user environments or systems where privilege boundaries must be strictly maintained, as a compromise of local administrative privileges can lead to total system takeover. Attacker capabilities require local access to the target machine and authorization to interact with the vulnerable subsystem. Exploitation requirements necessitate the attacker to successfully manipulate timing windows during concurrent operations involving shared resources managed by the backup engine. No network exposure is inherently required, as the attack vector is strictly local, but the security posture of the host is fundamentally undermined upon successful exploitation.",
  "technicalDetails": "The root cause of the vulnerability stems from improper synchronization during concurrent execution utilizing shared resources within the Windows Backup Engine. Specifically, the application fails to adequately protect critical sections, race conditions occur when multiple threads or processes attempt to access or modify shared system resources or file handles without appropriate locking mechanisms or atomic operations. The vulnerable component is the Windows Backup Engine, which processes local backup and restore operations. Authentication requirements dictate that the attacker must possess valid local credentials and be authorized to interact with the backup functionalities. Privilege requirements are minimal prior to exploitation, as the vulnerability is designed to elevate privileges locally from a standard user context. The network exposure is zero, classifying this strictly as a local privilege escalation vector. The exploitation method relies on the attacker initiating concurrent operations that target the race condition window. By meticulously timing requests or processes that contend for the shared resource managed by the Windows Backup Engine, the attacker can induce an inconsistent state or intercept operations mid-execution. For instance, this may involve manipulating temporary files, registry keys, or memory structures during backup routines before the engine applies proper security descriptors or access controls. The step-by-step attack flow involves: first, the local attacker establishes a baseline session on the target system; second, the attacker identifies the asynchronous or concurrent operational windows within the Windows Backup Engine where shared resources are accessed without synchronization; third, the attacker scripts or executes concurrent routines designed to race the legitimate engine process; fourth, upon successfully winning the race condition, the attacker intercepts or modifies the shared resource or object context; and fifth, the attacker leverages this manipulation to gain elevated code execution or administrative privileges. The post-exploitation impact includes full local privilege escalation, allowing the attacker to bypass operating system security controls, access sensitive system files, install unauthorized software, or compromise additional security domains residing on the same host."
}