CVE-2021-38646: in the CISA KEV catalogue
Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability. CISA added CVE-2021-38646 to the Known Exploited Vulnerabilities catalogue on 2022-03-28 with a default due date of 2022-04-18. Known ransomware campaign use: Known. Forensic triage flag: No.
Microsoft Office Access Connectivity Engine contains an unspecified vulnerability which can allow for remote code execution. (CISA description)
- Vendor / product
- Microsoft Office
- CWE
- Not listed
- CISA required action
- Apply updates per vendor instructions.
- EPSS
- 8.0%, percentile 94 (scored 2026-11-03)
EPSS puts about 8.0 in 100 odds (8.0%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 94% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.
Vendor and reference links (from CISA)
Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.
Frequently asked questions
Is CVE-2021-38646 in the CISA KEV catalogue?
Yes. CISA added CVE-2021-38646 (Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2022-03-28. CISA's default due date for it is 2022-04-18.
Is CVE-2021-38646 used in ransomware attacks?
CISA marks known ransomware campaign use as Known for CVE-2021-38646.
What should I do about CVE-2021-38646?
CISA's required action: Apply updates per vendor instructions.
Sources
- CISA, Known Exploited Vulnerabilities Catalog (accessed 2026-11-03)
- FIRST, Exploit Prediction Scoring System (EPSS) (EPSS by FIRST; scores generated by Empirical Security)
- NVD record for CVE-2021-38646