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CVE-2021-38646

61
FAUCET Score

CVE-2021-38646 is a remote code execution vulnerability affecting Microsoft Office and Microsoft 365 Apps, specifically within the Access Connectivity Engine. With a CVSS score of 7.8 (High), it allows an unauthenticated attacker to achieve high impact on confidentiality, integrity, and availability through a low-complexity attack requiring user interaction. This vulnerability is actively exploited in the wild, including in known ransomware campaigns, despite a lack of public exploit code in common repositories and limited community discussion.

Impacted Technologies

VendorProductVersion(s)CPE
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:*:*
2013CPE matchmatch criteria
cpe:2.3:a:microsoft:office:2013:sp1:*:*:-:*:*:*
2013CPE matchmatch criteria
cpe:2.3:a:microsoft:office:2013:sp1:*:*:rt:*:*:*
2016CPE matchmatch criteria
cpe:2.3:a:microsoft:office:2016:*:*:*:*:*:*:*
2019CPE matchmatch criteria
cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.8HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
4.40%
Probability of exploitation in next 30 days
EPSS Percentile
90.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
Added to KEV · Mar 28, 2022
This CVE's current EPSS score of 0.0440 is in the 91st percentile among its peer group of 11,621 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (10)

microsoftpatch availablevia nvd_reference
View patch
microsoftpatch availablevia msrc
Product: Microsoft Office 2019 for 32-bit editionsFixed in: https://aka.ms/OfficeSecurityReleases
microsoftpatch availablevia msrc
Product: Microsoft Office 2019 for 64-bit editionsFixed in: https://aka.ms/OfficeSecurityReleases
microsoftpatch availablevia msrc
Product: Microsoft 365 Apps for Enterprise for 32-bit SystemsFixed in: https://aka.ms/OfficeSecurityReleases
microsoftpatch availablevia msrc
Product: Microsoft 365 Apps for Enterprise for 64-bit SystemsFixed in: https://aka.ms/OfficeSecurityReleases
microsoftpatch availablevia msrc
Product: Microsoft Office 2016 (32-bit edition)Fixed in: 5215.1000
View patch
microsoftpatch availablevia msrc
Product: Microsoft Office 2016 (64-bit edition)Fixed in: 5215.1000
View patch
microsoftpatch availablevia msrc
Product: Microsoft Office 2013 RT Service Pack 1Fixed in: 5381.1000
microsoftpatch availablevia msrc
Product: Microsoft Office 2013 Service Pack 1 (32-bit editions)Fixed in: 5381.1000
View patch
microsoftpatch availablevia msrc
Product: Microsoft Office 2013 Service Pack 1 (64-bit editions)Fixed in: 5381.1000
View patch

Vendor Advisories (1)

microsoft2021-Sep/CVE-2021-38646Important

Microsoft Office Access Connectivity Engine Remote Code Execution Vulnerability

Sep 14, 2021

References

cisa.gov / known-exploited-vulnerabilities-catalog
US Government Resource
portal.msrc.microsoft.com / en-US/security-guidance/advisory/CVE-2021-38646
PatchVendor Advisory