Loading vulnerability…
CVE-2026-21251 is a local elevation-of-privilege vulnerability in the Windows Cluster Client Failover (CCF) component. The flaw is a use-after-free memory corruption condition caused by improper memory management in cluster failover handling, where a dangling pointer may be retained after the referenced object has been freed and later dereferenced. Available reporting indicates exploitation involves triggering cluster failover operations and reclaiming freed memory with attacker-controlled data before the stale pointer is used, enabling control over execution flow in the vulnerable code path. On affected Windows Server systems, successful exploitation can allow an authenticated local attacker to elevate privileges, potentially to SYSTEM.
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
If you can’t patch tonight, do this now.
Patch, then assume compromise.
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
9 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A privilege escalation vulnerability affecting Cluster Client Failover (CCF).
An elevation of privilege vulnerability in Cluster Client Failover (Windows Cluster Client Failover).
An elevation of privilege vulnerability in Cluster Client Failover (CCF) (no additional details provided in the content).
An elevation of privilege vulnerability in Cluster Client Failover (CCF).
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.