CVE-2026-21524
Published: 22 January 2026
Summary
CVE-2026-21524 is a high-severity Exposure of Sensitive Information to an Unauthorized Actor (CWE-200) vulnerability in Microsoft Azure Data Explorer. Its CVSS base score is 7.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 37.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and AC-4 (Information Flow Enforcement).
Deeper analysis
CVE-2026-21524 is a vulnerability in Azure Data Explorer that exposes sensitive information to an unauthorized actor. Classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor), it enables disclosure of sensitive data over a network. The issue carries a CVSS v3.1 base score of 7.4 (AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N) and was published on 2026-01-22.
An unauthorized attacker can exploit this vulnerability remotely over the network with low complexity and no required privileges, though user interaction is necessary. Scope changes upon successful exploitation (S:C), resulting in high-impact confidentiality loss (C:H) while leaving integrity and availability unaffected (I:N/A:N). This allows the attacker to obtain sensitive information from affected Azure Data Explorer instances.
Microsoft's Security Response Center provides an update guide for mitigation details at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21524.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-4501
Vulnerability details
Exposure of sensitive information to an unauthorized actor in Azure Data Explorer allows an unauthorized attacker to disclose information over a network.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Remote network exploitation of public-facing Azure service for sensitive data disclosure directly maps to T1190; resulting unauthorized access to cloud-hosted data enables T1530.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces access control policies to block unauthorized actors from reading sensitive data in Azure Data Explorer.
Enforces information flow rules that prevent unauthorized network disclosure of sensitive information from the data explorer service.
Requires cryptographic protection of data in transit, mitigating the network-based exposure described in the CVE.