CVE-2021-43928Network attack vector

Authenticated command execution via undisclosed vectors

Published Feb 7, 2022 · Updated Sep 17, 2024

OS command injection in Synology Mail Station before 20211105-10315 allows remote authenticated users to execute arbitrary commands. Synology identifies the mail sending and receiving component but has not published the affected code path, input field, or failed neutralization operation. A valid Mail Station account and network access to the service are required, and successful exploitation executes commands in the appliance environment.

CVSS severity9.9
Critical
EPSS probability1.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in Synology Mail Station before 20211105-10315 allows remote authenticated users to execute arbitrary commands. Synology identifies the mail sending and receiving component but has not published the affected code path, input field, or failed neutralization operation. A valid Mail Station account and network access to the service are required, and successful exploitation executes commands in the appliance environment.

The record

CVE
CVE-2021-43928
Published
Feb 7, 2022
Updated
Sep 17, 2024
Vendor
Synology
Product
Mail Station
Classifications
CWE-78, T1059
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 7, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record 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.

  1. Affected versionversion=unspecified <20211105-10315

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Synology · Mail Stationversion=unspecified <20211105-10315

Published CVSS scores

6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
9.9Synology Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

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.

Technologies

Your stack

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Your stack

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