Description

Observable response discrepancy in Azure Stack HCI allows an unauthorized attacker to disclose information over a network.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.6",
  "pubDate": "2026-08-20T22:18:00.123Z",
  "pubdate": "2026-08-20T22:18:00.123Z",
  "executiveSummary": "An information disclosure vulnerability exists in Azure Stack HCI due to an observable response discrepancy. This security flaw allows an unauthenticated, unauthorized remote attacker to harvest sensitive system or operational data over the network by analyzing differential responses from the target application or service. The primary impact of this vulnerability is the compromise of confidentiality, potentially exposing internal architectural details, configurations, or operational state data that could facilitate subsequent attack vectors. The affected product is Azure Stack HCI. Exploitation requires network connectivity to the vulnerable endpoint and does not necessitate prior authentication or elevated privileges. The risk implication is moderate to high depending on the sensitivity of the leaked response data. Defensive posture requires restricting unauthorized network access, implementing uniform error handling and response times to mitigate oracle-based or discrepancy-based inference attacks, and applying official vendor-supplied updates as soon as they become available.",
  "technicalDetails": "The vulnerability stems from an observable response discrepancy within Azure Stack HCI network-facing components. In software engineering and security architecture, a response discrepancy occurs when an application or service returns measurably different outputs, error messages, status codes, or execution timing based on internal states, data existence, or query validity. An unauthorized remote attacker leverages this behavior to construct analytical probes over the network. By systematically sending crafted requests and observing the differential properties of the resulting responses, the attacker can infer sensitive information that should otherwise remain concealed. The vulnerable component is part of the network service interface within Azure Stack HCI. Exploitation can be executed remotely over the network without requiring user interaction, authentication, or privileges. The attack flow typically begins with the reconnaissance phase, where the attacker maps the behavioral profile of the target service. Following the establishment of a baseline, the attacker transmits targeted payloads designed to elicit conditional execution paths. By analyzing the nuanced variations in the observable responses—such as differing payload lengths, specific error codes, or subtle latency deltas—the attacker reconstructs the underlying data structures or confirms the presence or absence of specific internal records. This methodology operates as an inference-based side-channel or oracle attack, bypassing traditional access controls because the exposed information is indirectly leaked through differential system feedback rather than explicit data access authorization. Post-exploitation impact is strictly centered on information disclosure, where the harvested intelligence can be chained with other vulnerabilities to achieve deeper network penetration, privilege escalation, or targeted system compromise."
}