Microsoft Azure Kubernetes Configuration Service: Elevation of privilege via missing authentication

Summary

Microsoft Azure Kubernetes Configuration Service contains a missing authentication check for a critical function (CWE-306). According to the CVE record, an unauthenticated attacker with network access can elevate privileges, with a CVSS 3.1 base score of 10.0 (Critical). Microsoft states that the issue has been fully mitigated on its service side and that customers have no action to take.

Affected

• Microsoft Azure Kubernetes Configuration Service
• Customer-facing version numbers: Unknown.
• A third-party tracker lists all versions as affected; this is not confirmed by Microsoft.

Fixed in

• Mitigated server-side by Microsoft; no customer update required.
• Customer-facing fixed version: Unknown.

Workaround

• None required from customers, according to Microsoft.
• No customer-side workaround identified.

Exploitation

• Not listed in the CISA KEV catalogue. EPSS: Unknown.
• Microsoft temporal metrics: Exploit Code Maturity Unproven (E:U).
• No public proof-of-concept or reports of in-the-wild exploitation found at the time of research.
• CISA SSVC: Exploitation none, Automatable yes, Technical Impact total.

Our recommendation

• No customer action is documented by Microsoft; record the CVE as vendor-mitigated for affected Azure tenants.
• Monitor the MSRC Security Update Guide and Azure/AKS advisories for customer guidance.
• Re-check public exploit status in about one week.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

Links to third-party sites, not checked by us – exploit code can contain malware. Only use it in isolated test environments.

• Proof of concept on GitHub (1 repositories) iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).
  mehmet-emir-eroglu/CVE-2026-83938

Research sources

• Microsoft Security Update Guide: CVE-2026-83938 msrc.microsoft.com
• Rapid7 vulnerability database entry www.rapid7.com
• VulDB entry vuldb.com
• OffSeq threat radar entry radar.offseq.com
• Positive Technologies via Vulners vulners.com
• MSRC security guidance msrc.microsoft.com

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 30 Oct 2026, 13:56.