CVE-2021-27556Public exploitNetwork attack vector

Administrator command execution via unrestricted Cron type

Published Aug 31, 2021 · Updated Aug 3, 2024

OS command injection in EasyCorp ZenTao 12.5.3 allows remote authenticated users with administrator access to execute arbitrary code. The Cron job update handler accepts arbitrary zt_cron fields, allowing type to be changed to system so control.php passes the stored command to exec(). Administrator access is required; a crafted Cron job runs attacker-supplied commands with the ZenTao service account's privileges.

CVSS severity7.2
High
EPSS probability4.01%
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 EasyCorp ZenTao 12.5.3 allows remote authenticated users with administrator access to execute arbitrary code. The Cron job update handler accepts arbitrary zt_cron fields, allowing type to be changed to system so control.php passes the stored command to exec(). Administrator access is required; a crafted Cron job runs attacker-supplied commands with the ZenTao service account's privileges.

The record

CVE
CVE-2021-27556
Published
Aug 31, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-78, T1059
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Aug 31, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.0NIST NVDAV:N/AC:L/Au:S/C:C/I:C/A:C
7.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/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.

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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

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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