CVE-2021-36426Public exploitNetwork attack vector

Authenticated code execution via unchecked upload extension

Published Feb 3, 2023 · Updated Mar 26, 2025

Unrestricted file upload in phpwcms 1.9.25 allows remote authenticated users to execute PHP code through the campaign manager. The image-upload path in include/inc_lib/general.inc.php trusts getimagesize output without separately validating the filename extension, so a polyglot image with a .php suffix is stored beneath content/marketing and remains web-executable. Backend access is required; successful exploitation executes attacker-supplied PHP in the web server context, enabling control of application data and service operation.

CVSS severity8.8
High
EPSS probability1.06%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in phpwcms 1.9.25 allows remote authenticated users to execute PHP code through the campaign manager. The image-upload path in include/inc_lib/general.inc.php trusts getimagesize output without separately validating the filename extension, so a polyglot image with a .php suffix is stored beneath content/marketing and remains web-executable. Backend access is required; successful exploitation executes attacker-supplied PHP in the web server context, enabling control of application data and service operation.

The record

CVE
CVE-2021-36426
Published
Feb 3, 2023
Updated
Mar 26, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-434, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 3, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 26, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/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 exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1190Exploit Public-Facing Application

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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