Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability
Microsoft Office Access Connectivity Engine contains an unspecified vulnerability which can allow for remote code execution.
- Vendor
- Microsoft
- Product
- Office
- CVSS
- 7.8
- EPSS (exploit probability)
- 8.0%
- Status
- kevransomware use
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2021-38646 being exploited?
Yes. CISA added CVE-2021-38646 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild. CISA marks it as known to be used in ransomware campaigns.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 8.0% (scored October 14, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-11-13. Full cross-catalog view: /kev-comparison
CVE-2021-38646 timeline
Every event links to its source. Catalog dates are each catalog's own; day offsets count from NVD publication. Data: JSON
What to do
CISA required actionApply updates per vendor instructions.
US federal civilian agencies must remediate by (21 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Microsoft Office CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2026-124194 Microsoft Office Outlook Missing User Interaction for Potentially Unsafe Action Vulnerability | [ MEDIUM ] | 6.5 | 1.6% | |
| CVE-2009-0238 Microsoft Office Remote Code Execution | [ HIGH ] | 8.8 | 42.9% | |
| CVE-2026-21514 Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision Vulnerability | [ HIGH ] | 7.8 | 1.6% | |
| CVE-2026-21509 Microsoft Office Security Feature Bypass Vulnerability | [ HIGH ] | 7.8 | 70.8% | |
| CVE-2009-0556 Microsoft Office PowerPoint Code Injection Vulnerability | [ HIGH ] | 8.8 | 67.3% | |
| CVE-2007-0671 Microsoft Office Excel Remote Code Execution Vulnerability | [ HIGH ] | 8.8 | 44.1% | |
| CVE-2023-23397 Microsoft Office Outlook Privilege Escalation Vulnerability | [ CRITICAL ] | 9.8 | 97.2% | |
| CVE-2023-21715 Microsoft Office Publisher Security Feature Bypass Vulnerability | [ HIGH ] | 7.3 | 12.0% |