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 22.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Automated marking applies security attributes to system outputs, making it harder for attackers to exploit unmarked sensitive information leading to unauthorized exposure.
Proper attribute retention and permitted-value enforcement limits unauthorized actors from accessing sensitive information lacking correct labels.
Prevents unauthorized exposure of sensitive information by prohibiting untrusted external systems from processing or storing it.
By enforcing authorization matching prior to sharing, the control reduces the risk of exposing sensitive information to unauthorized actors.
Review and removal of nonpublic information from publicly accessible systems directly prevents exposure of sensitive data to unauthorized actors.
Data mining protection mechanisms detect and block unauthorized bulk extraction of sensitive data, directly mitigating exposure to unauthorized actors.
Literacy training teaches users to recognize and avoid actions that result in unauthorized exposure of sensitive information.
Retaining and monitoring training records confirms personnel have completed privacy and security awareness training on handling sensitive data, reducing the chance of unauthorized exposure due to lack of knowledge.
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.
NVD Description
Exposure of sensitive information to an unauthorized actor in Azure Data Explorer allows an unauthorized attacker to disclose information over a network.
Deeper analysisAI
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.
Details
- CWE(s)