Exploited· due 2022-04-187.8highHighused in ransomware
CVE-2021-38646
Microsoft 365 Apps
Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability
Exploitation status
- CISA has confirmed this is being exploited in the wild. That is an observation of real attacks, not a prediction.
- It is known to have been used in ransomware campaigns.
- US federal civilian agencies are required to remediate it by 2022-04-18. That deadline does not bind private companies, but it is a reasonable benchmark for how urgently CISA views it.
- A vendor advisory or patch reference has been published.
Required action
Apply updates per vendor instructions.
CISA’s wording, unedited.
What the metrics mean
- It is requires local access to the machine.
- For an attacker who can reach it, no special conditions are needed to exploit it.
- To exploit it, no account is needed.
- Beyond that, someone has to be persuaded to take an action first.
Scoring
- CVSS
- 7.8 (v3.1)
- Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H- Assigned by
- secure@microsoft.com
Dates
- Published
- 2021-09-15
- Last modified
- 2026-08-10
- Added to KEV
- 2022-03-28
- Remediation due
- 2022-04-18
- Sources
- CISA KEV, NVD
Affected products
- Microsoft 365 Appsall versions
- Microsoft Office2013
- Microsoft Office 2016all versions
- Microsoft Office 2019all versions
As listed in the NVD configuration data. Not a statement about your estate.