CVE-2021-46686Network attack vector

Unauthenticated remote OS command execution

Published Feb 17, 2025 · Updated Feb 18, 2025

OS command injection in acmailer CGI 4.0.3 and earlier and acmailer DB 1.1.5 and earlier allows remote attackers to execute commands. The vendor and JPCERT/CC have not published the affected parameter, code path, or command-building operation that fails to neutralize untrusted input. No authentication or user interaction is required, and successful exploitation runs arbitrary OS commands and can expose mailing lists and stored credentials on the server.

CVSS severity9.8
Critical
EPSS probability1.42%
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 acmailer CGI 4.0.3 and earlier and acmailer DB 1.1.5 and earlier allows remote attackers to execute commands. The vendor and JPCERT/CC have not published the affected parameter, code path, or command-building operation that fails to neutralize untrusted input. No authentication or user interaction is required, and successful exploitation runs arbitrary OS commands and can expose mailing lists and stored credentials on the server.

The record

CVE
CVE-2021-46686
Published
Feb 17, 2025
Updated
Feb 18, 2025
Vendor
Extra Innovation Inc.
Product
acmailer DB
Classifications
CWE-78, T1059
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 17, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 18, 2025Record 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=ver.1.1.5 and earlier

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Extra Innovation Inc. · acmailer DBversion=ver.1.1.5 and earlier
Extra Innovation Inc. · acmailer CGIversion=ver.4.0.3 and earlier

Published CVSS scores

9.8JPCERT/CCCVSS:3.0/AV:N/AC:L/PR:N/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
Privilegesunauthenticated
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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