Windows Defender
CVE-2021-31978 — Microsoft Defender Denial of Service Vulnerability
Executive Summary
None
Overview
5.5
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H/E:U/RL:O/RC:CATTACK VECTOR
Local
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
Required
SCOPE
Unchanged
CONFIDENTIALITY
None
INTEGRITY
None
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 4.8
EPSS Score
0.01225
probability of exploitation in the next 30 days
0.66166 percentile - updated 2026-08-14
View on FIRST.orgAffected Products
1 affected product
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Microsoft Malware Protection Engine | Release Notes (Security Update) | Important | Denial of Service | No |
Patches
1 patch
| Article | Type | Restart |
|---|---|---|
Release Notes | Security Update | No |
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
Tavis Ormandy of Google Project Zero
References
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