CVE-2026-33105: Microsoft Patches CVSS 10.0 Auth Bypass in Azure Kubernetes Service

Microsoft disclosed CVE-2026-33105 on April 3, 2026 — a CVSS 10.0 improper authorization vulnerability in Azure Kubernetes Service. An unauthenticated attacker with network access can bypass RBAC controls and escalate privileges to gain full control of containerized workloads running on affected AKS clusters.

A score of 10.0 is the ceiling. No credentials needed. No user interaction required. Network-reachable.

What’s affected

The flaw exists in AKS’s authorization layer. An attacker positioned on the network — inside the same VNet, or externally if the API server is exposed — can send crafted requests that bypass role-based access checks. From there, privilege escalation to cluster-admin-level control is possible, allowing arbitrary workload modification, secret extraction, and lateral movement across the cluster.

Microsoft has not published specific version ranges for the patch. The fix was deployed automatically via Azure Update Manager. If your AKS clusters are set to receive managed updates, the patch should already be applied. If your clusters are on a manual update cadence, check your AKS version immediately.

Fix: Update to the latest AKS patch via Azure Update Manager or run az aks upgrade to pull the corrected control plane version. Verify your cluster version in the Azure portal under Kubernetes version — any version released before April 3, 2026 should be confirmed as patched before treating it as resolved.

The companion vulnerability

The same April patch cycle surfaced CVE-2026-32213 — also rated CVSS 10.0 — in Azure AI Foundry, Microsoft’s platform for building and deploying AI applications. Details on the exact attack vector are limited, but the disclosure pattern (two maximum-severity flaws in adjacent cloud services, same week) points to a coordinated audit or responsible disclosure process rather than opportunistic discovery.

What to do right now

1. Confirm all AKS clusters are running post-April 3 control plane versions.
2. Audit AKS API server network exposure — clusters with public API server endpoints are higher risk.
3. Review RBAC role assignments for any unexpected escalations that may have occurred before the patch window.
4. If running Azure AI Foundry, apply CVE-2026-32213 patches and review AI endpoint authentication settings.

No in-the-wild exploitation has been reported as of the disclosure date, but CVSS 10.0 vulnerabilities in widely-used managed Kubernetes services historically move from PoC to active exploitation in days.

The timeline pressure is real. AKS runs production workloads for a significant share of enterprise cloud infrastructure. Treat this as a patch-now event.