Microsoft · Office
CVE-2021-38646
Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability
Exploited in attacks
Used by ransomware
High 7.8 Attack chance: 8.0%
What it is
Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability
CISA: Microsoft Office Access Connectivity Engine contains an unspecified vulnerability which can allow for remote code execution.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: April 18, 2022
More exploited flaws from Microsoft
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Apr 14, 2026 | Remote Code Execution | Office | High 8.8 | 43% |
| Feb 10, 2026 | Word Reliance on Untrusted Inputs in a Security Decision | Office | High 7.8 | 1.6% |
| Jan 26, 2026 | Security Feature Bypass | Office | High 7.8 | 71% |
| Jan 7, 2026 | PowerPoint Code Injection | Office | High 8.8 | 67% |
| Aug 12, 2025 | Excel Remote Code Execution | Office | High 8.8 | 43% |
| Mar 14, 2023 | Outlook Privilege Escalation | Office | Critical 9.8 | 97% |
| Feb 14, 2023 | Publisher Security Feature Bypass | Office | High 7.3 | 12% |
| Jun 8, 2022 | Object Record Corruption | Office | High 7.8 | 53% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.