cve 2026 21251

About this tag
CVE-2026-21251 is a Cluster Client Failover (CCF) elevation-of-privilege vulnerability affecting Windows Failover Clusters. Microsoft's Security Response Center has published an advisory with a high confidence rating, urging immediate attention from Windows administrators, security teams, and enterprise IT professionals who manage failover clusters in production environments. The vulnerability targets cluster membership components, potentially allowing an attacker to elevate privileges within the cluster. Hardening measures and patching are critical to mitigate risks. This tag covers discussions, advisories, and remediation steps related to CVE-2026-21251, focusing on Windows Server security and cluster resilience.

  1. CVE-2026-21251: Hardening Windows Failover Clusters Against CCF Elevation of Privilege

    Microsoft’s Security Response Center has published an advisory entry for CVE‑2026‑21251 — labeled as a Cluster Client Failover (CCF) elevation‑of‑privilege issue — and paired it with a confidence rating that deserves immediate attention from Windows administrators, security teams, and anyone who...
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