CVE-2021-38646
Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability
- High 7.8
- Exploited: added to CISA KEV 28 Mar 2022
- Used in ransomware campaigns
Description
Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability
Key facts
- Published
- 15 Sep 2021
- Last changed
- 10 Aug 2026
- Assigned by
- microsoft
- KEV added
- 28 Mar 2022
- KEV fix due
- 18 Apr 2022
- Used in ransomware
- Yes, according to CISA
- EPSS
- 7.987% likely to be exploited in the next 30 days, higher than 94.847% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: active; Automatable: no; Technical impact: total
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 7.8CVSS 3.1, Highfrom the CNA (microsoft)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
What to do
- Apply updates per vendor instructions.CISA KEV required action
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft 365 Apps for Enterprise |
|
| Microsoft | Microsoft Office 2013 Service Pack 1 |
|
| Microsoft | Microsoft Office 2016 |
|
| Microsoft | Microsoft Office 2019 |
|
Timeline
- 15 Sep 2021 Published
- 28 Mar 2022 CVE-2021-38646 added to CISA KEV
- 28 Mar 2022 Added to the CISA KEV catalogue