CVE-2026-21251
Cluster Client Failover (CCF) Elevation of Privilege Vulnerability
Description
Use after free in Windows Cluster Client Failover allows an authorized attacker to elevate privileges locally.
INFO
Published Date :
Feb. 10, 2026, 6:16 p.m.
Last Modified :
Feb. 10, 2026, 9:51 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-21251
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Apply the latest Windows security updates.
- Ensure all cluster nodes are patched.
- Monitor for unauthorized privilege changes.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-21251.
| URL | Resource |
|---|---|
| https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21251 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-21251 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-21251
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-21251 vulnerability anywhere in the article.
-
Zero Day Initiative
The February 2026 Security Update Review
I have survived the biggest Pwn2Own ever, but I’m back in Tokyo for the second Patch Tuesday of 2026. My location never stops Patch Tuesday from coming, so let’s take a look at the latest security pat ... Read more
-
CybersecurityNews
Microsoft Patch Tuesday February 2026 – 54 Vulnerabilities Fixed, Including 6 Zero-days
Microsoft Patch Tuesday February 2026 Microsoft released its February 2026 Patch Tuesday updates on February 10, addressing 54 vulnerabilities, including six zero-days across Windows, Office, Azure, a ... Read more
The following table lists the changes that have been made to the
CVE-2026-21251 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Feb. 10, 2026
Action Type Old Value New Value Added Description Use after free in Windows Cluster Client Failover allows an authorized attacker to elevate privileges locally. Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-416 Added Reference https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21251