Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Microsoft Azure Attestation service and Device Health Attestation Service allows an unauthorized attacker to execute code over a network.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.1",
  "pubDate": "2026-08-11T17:19:01.587Z",
  "pubdate": "2026-08-11T17:19:01.587Z",
  "executiveSummary": "A concurrency vulnerability categorized as a race condition involving shared resource access with improper synchronization has been identified within the Microsoft Azure Attestation service and the Device Health Attestation Service. This security flaw enables an unauthorized remote threat actor to execute arbitrary code over a network without requiring prior authentication or privileged access.\nThe vulnerability stems from improper synchronization mechanisms when multiple concurrent execution threads access shared resources, creating a window of vulnerability that can be manipulated during execution timing. Successful exploitation of this flaw can compromise the integrity and availability of the affected attestation services, potentially leading to unauthorized code execution within the context of the service.\nThe risk implications are significant due to the network-accessible nature of the Microsoft Azure Attestation service and Device Health Attestation Service, allowing remote attackers to target vulnerable instances directly. Exploitation requires precise timing coordination to win the race condition and manipulate the shared resource state before synchronization mechanisms resolve.\nOrganizations relying on these Microsoft services must evaluate their exposure and implement available vendor-supplied updates or compensating controls to mitigate the risk of remote code execution arising from synchronization flaws.",
  "technicalDetails": "The root cause of the vulnerability resides in the concurrent execution of code paths that access shared resources without adequate locking, mutexes, or proper synchronization primitives within the Microsoft Azure Attestation service and Device Health Attestation Service. When multiple threads attempt to read, write, or modify the same underlying memory structures or operational states simultaneously, a race condition occurs.\nThe vulnerable components are the core service handlers responsible for processing attestation requests over a network protocol. Because these endpoints are exposed remotely, an unauthorized attacker can transmit carefully crafted sequences of concurrent requests designed to overlap timing windows during shared resource access.\nThe attack flow proceeds as follows: First, the attacker establishes network connectivity to the targeted attestation endpoint. Second, the attacker initiates a high volume of concurrent requests or specific timing-skewed payloads engineered to target the unsynchronized execution path. Third, as the Microsoft Azure Attestation service and Device Health Attestation Service process these requests across multiple threads, the race condition is triggered when thread scheduling interleaves operations on the shared resource in an unintended sequence.\nThis improper interleaving leads to memory corruption, inconsistent state evaluation, or logic bypasses, which the attacker subsequently steers to achieve arbitrary code execution. The vulnerability does not require authentication or elevated privileges, lowering the complexity barrier for network-based exploitation. The post-exploitation impact includes potential execution of attacker-supplied payloads within the service boundary, jeopardizing the trust guarantees provided by the attestation infrastructure."
}