Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows DNS allows an authorized attacker to execute code over a network.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.6",
  "pubDate": "2026-08-11T17:18:14.193Z",
  "pubdate": "2026-08-11T17:18:14.193Z",
  "executiveSummary": "A vulnerability classified as a concurrent execution using shared resource with improper synchronization, commonly known as a race condition, exists within the Windows DNS component. This security flaw enables an authorized attacker to achieve remote code execution over a network.\nThe vulnerability directly impacts the Windows DNS service, a core component responsible for name resolution across enterprise and standalone environments. Successful exploitation carries severe risk implications, potentially granting the adversary unauthorized control over the affected infrastructure.\nThe attacker capabilities required to exploit this vulnerability include network access to the target system and authorized status. Exploitation relies on leveraging improper synchronization mechanisms during concurrent execution flows to trigger memory corruption or state manipulation.\nGiven that the flaw resides in a fundamental networking service, unauthorized code execution could lead to complete system compromise, lateral movement within the network, and further dissemination of malicious payloads.",
  "technicalDetails": "The root cause of the vulnerability stems from inadequate synchronization handling of shared resources during concurrent execution threads within the Windows DNS service. Specifically, when multiple threads access or modify shared memory structures without proper locking mechanisms or atomic operations, a race condition occurs.\nThe vulnerable component is the Windows DNS service execution pipeline, which processes incoming network requests and manages internal state tables. Affected versions encompass the standard implementations of Windows DNS where this improper synchronization flaw remains unpatched.\nExploitation requires the attacker to possess network exposure to the target DNS server and valid authorization credentials to interact with the service. The privilege requirements depend on the specific interface targeted, but network-based interaction is a prerequisite.\nThe attack flow proceeds as follows: First, the authorized attacker initiates multiple concurrent network requests directed at the Windows DNS service designed to target the vulnerable shared resource. Second, by precisely timing these asynchronous or multi-threaded requests, the attacker induces a race condition window where internal synchronization checks fail.\nThird, this failure allows the manipulation of shared memory pointers or data structures in an unintended sequence, leading to a state of memory corruption, such as a use-after-free or invalid pointer dereference. Finally, the attacker crafts a specialized payload delivered through the network to hijack the execution flow, resulting in arbitrary code execution within the context of the service.\nThe post-exploitation impact of this vulnerability is critical. Because the Windows DNS service typically operates with elevated privileges, achieving code execution via this race condition allows the adversary to execute arbitrary binaries, install persistence mechanisms, pivot to other internal network segments, and compromise the underlying operating system entirely."
}