PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-47280 Microsoft CVE debrief

A critical authentication bypass vulnerability in Azure Resource Manager (ARM) enables unauthenticated network-based privilege escalation. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H) indicates network attack vector, low complexity, no privileges required, no user interaction, and changed scope with high impact across confidentiality, integrity, and availability. The vulnerability is classified under CWE-287 (Improper Authentication). Microsoft has acknowledged this issue through their Security Response Center. The CVE was published on 2026-05-22 and last modified on 2026-05-26, with NVD status currently 'Undergoing Analysis'. No known exploitation in ransomware campaigns has been documented (KEV: false).

Vendor
Microsoft
Product
Azure Resource Manager
CVSS
CRITICAL 10
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-22
Original CVE updated
2026-05-27
Advisory published
2026-05-22
Advisory updated
2026-05-27

Who should care

Azure administrators, cloud security architects, identity and access management teams, SOC analysts monitoring Azure environments, organizations with Azure AD-integrated infrastructure, and compliance officers responsible for cloud security posture management.

Technical summary

The vulnerability stems from improper authentication mechanisms within Azure Resource Manager, Microsoft's deployment and management service for Azure. The flaw allows attackers to bypass authentication controls entirely over network paths, subsequently elevating privileges without valid credentials. The scope change (S:C) in CVSS scoring suggests the vulnerability may enable impact beyond the initially compromised security scope, potentially affecting multiple Azure subscriptions or management groups within a tenant. The network-accessible, unauthenticated nature combined with critical impact ratings indicates this vulnerability could enable widespread unauthorized cloud resource manipulation if exploited.

Defensive priority

P0

Recommended defensive actions

  • Monitor Microsoft Security Response Center (MSRC) for security update availability and deployment guidance
  • Review Azure Resource Manager access logs for anomalous privilege escalation attempts from unauthenticated sources
  • Apply authentication hardening controls for ARM API endpoints pending patch availability
  • Validate conditional access policies and multi-factor authentication enforcement for Azure management operations
  • Subscribe to Azure service health notifications for security-related service advisories

Evidence notes

Official CVE record confirms Azure Resource Manager as affected product. Microsoft MSRC reference validates vendor acknowledgment. CVSS 10.0 score and CRITICAL severity confirmed by NVD. CWE-287 classification sourced from [email protected] submission. Vendor attribution marked 'needsReview' with low confidence due to 'Unknown Vendor' placeholder in source data, though Microsoft evidence is present.

Official resources

2026-05-22T23:16:56.407Z