CVE-2021-40449

What is affected

Vendor	Microsoft
Product	Windows
Weakness	CWE-416

The vulnerability

Unspecified vulnerability allows for an authenticated user to escalate privileges.

Required action

Apply updates per vendor instructions.

US federal civilian agencies were required to act by 1 December 2021 under BOD 22-01. The deadline is a compliance date, not a measure of severity — it says nothing about how dangerous the flaw is to anyone else.

Ransomware

CISA records this vulnerability as having been used in ransomware campaigns. That is a confirmed observation, not an assessment of likelihood.

Where this comes from

Every field on this page is taken from the CISA Known Exploited Vulnerabilities catalog, last synced 11 Nov 2026, 21:30. Nothing here is our own assessment. For the technical scoring, see the NVD record below.

NVD record ↗ CVE.org record ↗