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CVE-2021-43928

28
FAUCET Score

CVE-2021-43928 is an OS Command Injection vulnerability affecting Synology Mail Station versions prior to 20211105-10315. This flaw allows remote authenticated users to execute arbitrary commands through unspecified vectors within the mail sending and receiving components. With a CVSS score of 8.8 (High), this vulnerability presents a significant risk due to its network-based attack vector, low attack complexity, and potential for high impact on confidentiality, integrity, and availability. Currently, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 20211105CPE matchmatch criteria
cpe:2.3:a:synology:mail_station:*:*:*:*:*:*:*:*
< 20211105-10315CPE match
cpe:2.3:a:synology:mail_station:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.9CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.1
Impact Score
6.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.86%
Probability of exploitation in next 30 days
EPSS Percentile
77.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0186 is in the 75th percentile among its peer group of 17,844 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.3 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

synology.com / security/advisory/Synology_SA_21_28
Vendor Advisory