CVE-2021-47667Public exploitNetwork attack vector

Unauthenticated command execution via tmp_name shell injection

Published Apr 5, 2025 · Updated Apr 7, 2025

OS command injection in ZendTo 5.24-3 through 6.x before 6.10-7 allows remote attackers to execute arbitrary commands through file drop-off. NSSDropoff copies the untrusted tmp_name JSON value into a file list that it concatenates without shell escaping into chmod and ClamAV command lines. The path is reachable without authentication when anonymous drop-off and ClamAV scanning are enabled, and commands run with the service's privileges.

CVSS severity10.0
Critical
EPSS probability36.61%
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 ZendTo 5.24-3 through 6.x before 6.10-7 allows remote attackers to execute arbitrary commands through file drop-off. NSSDropoff copies the untrusted tmp_name JSON value into a file list that it concatenates without shell escaping into chmod and ClamAV command lines. The path is reachable without authentication when anonymous drop-off and ClamAV scanning are enabled, and commands run with the service's privileges.

The record

CVE
CVE-2021-47667
Published
Apr 5, 2025
Updated
Apr 7, 2025
Vendor
ZendTo
Product
ZendTo
Classifications
CWE-78, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 7, 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=5.24-3 <6.10-7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ZendTo · ZendToversion=5.24-3 <6.10-7

Published CVSS scores

10.0MITRECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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.

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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 exploitPublished

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Unix Shell

Public exploit references

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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