Role: Windows AD FS Server
CVE-2021-40456 — Windows AD FS Security Feature Bypass Vulnerability
Executive Summary
None
Overview
5.3
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
Low
INTEGRITY
None
AVAILABILITY
None
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 4.6
EPSS Score
0.02215
probability of exploitation in the next 30 days
0.80326 percentile - updated 2026-06-21
View on FIRST.org
Affected Products
6 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Windows Server 2019 | 5006672 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server 2019 (Server Core installation) | 5006672 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server 2022 | 5006699 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server 2022 (Server Core installation) | 5006699 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server, version 2004 (Server Core installation) | 5006670 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server, version 20H2 (Server Core Installation) | 5006670 (Security Update) |
Important | Security Feature Bypass | Yes |
Patches
3 patches
| Article | Type | Restart |
|---|---|---|
5006672 |
Security Update | Yes |
5006699 |
Security Update | Yes |
5006670 |
Security Update | Yes |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
None
References
On This Page