Code execution via undisclosed engine flaw
Published Sep 15, 2021 · Updated Aug 10, 2026
Remote code execution in Microsoft Office Access Connectivity Engine allows attackers to execute code after required user interaction. Microsoft has not published the flawed operation or the attacker-controlled input processed by the engine. Exploitation requires user interaction and executes code in the affected Office user's security context.
Summary
What happened
Remote code execution in Microsoft Office Access Connectivity Engine allows attackers to execute code after required user interaction. Microsoft has not published the flawed operation or the attacker-controlled input processed by the engine. Exploitation requires user interaction and executes code in the affected Office user's security context.
The record
- CVE
- CVE-2021-38646
- Published
- Sep 15, 2021
- Updated
- Aug 10, 2026
- Vendor
- Microsoft
- Product
- Microsoft Office 2016
- Classifications
- T1204
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 15, 2021CVE publishedPublication date reported by the CVE source.
- Mar 28, 2022Exploitation reportedCISA Known Exploited Vulnerabilities listing
- Aug 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=16.0.0 <5215.1000
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- Ransomware campaign useransomware
- CISA Known Exploited Vulnerabilities listingknown exploited catalog
Technologies
Your stack
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Your stack
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