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CVE-2021-31166: Microsoft HTTP Protocol Stack Remote Code Execution Vulnerability
Microsoft HTTP Protocol Stack · in CISA KEV since 2022-04-06
2022-04-06added to KEV
2022-04-27federal remediation due date
99.77%EPSS exploit probability (30 days) 100.0th percentile
9.8 CRITICALCVSS 3.1
Unknownknown ransomware use
330days from NVD publication to KEV
What it is
Microsoft HTTP Protocol Stack contains a vulnerability in http.sys that allows for remote code execution.
Required action (CISA)
Apply updates per vendor instructions.
| CWE | CWE-416 |
|---|---|
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD published | 2021-05-11 (Analyzed) |
Original records: NVD · CISA KEV · JSON: /api/cve/CVE-2021-31166.json · all KEV CVEs
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Get the full file: Exploited Vulnerabilities Brief – September 2026 ($29): this month's KEV additions ranked by EPSS, ransomware use and due date, ready to hand to a patch team. Checkout by Polar.
Get the full file: Exploited Vulnerabilities Brief – September 2026 ($29): this month's KEV additions ranked by EPSS, ransomware use and due date, ready to hand to a patch team. Checkout by Polar.