MSRC-CVE-2025-55321 — Azure Monitor Log Analytics Spoofing Vulnerability

Summary

Impact: Spoofing. Microsoft rating: Critical. Not known to be exploited — Exploitation Less Likely. Customer action: Not required.

Details

Why are there no links to an update or instructions with steps that must be taken to protect from this vulnerability?
This vulnerability has already been fully mitigated by Microsoft. There is no action for users of this service to take. The purpose of this CVE is to provide further transparency.
Please see Toward greater transparency: Unveiling Cloud Service CVEs for more information.

Vulnerabilities 1

Critical 9.3

CVE-2025-55321

Azure Monitor Log Analytics Spoofing Vulnerability

Improper neutralization of input during web page generation ('cross-site scripting') in Azure Monitor allows an unauthorized attacker to perform spoofing over a network.

Microsoft Azure Monitor

Oct 9, 2025

Revision history

2025-10-09 #1
Information published.

References

CVE-2025-55321 Azure Monitor Log Analytics Spoofing Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-55321
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss