CVE-2021-24224Network attack vector

Authenticated remote code execution via unrestricted upload

Published Apr 12, 2021 · Updated Aug 3, 2024

Unrestricted file upload in WhiteStudio Easy Form Builder 1.0 and earlier allows remote authenticated users to execute PHP code. EFBP_verify_upload_file_callback passes each supplied filename into wp-content/uploads/formbuilder and move_uploaded_file without blocking PHP extensions. Any low-privilege WordPress account can place an executable PHP file in the web-accessible upload directory, enabling remote code execution.

CVSS severity8.8
High
EPSS probability1.91%
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 WhiteStudio Easy Form Builder 1.0 and earlier allows remote authenticated users to execute PHP code. EFBP_verify_upload_file_callback passes each supplied filename into wp-content/uploads/formbuilder and move_uploaded_file without blocking PHP extensions. Any low-privilege WordPress account can place an executable PHP file in the web-accessible upload directory, enabling remote code execution.

The record

CVE
CVE-2021-24224
Published
Apr 12, 2021
Updated
Aug 3, 2024
Vendor
WhiteStudio
Product
Easy Form Builder
Classifications
CWE-434, T1505.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 12, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0 <=1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

WhiteStudio · Easy Form Builderversion=1.0 <=1.0

Published CVSS scores

8.8NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.5NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

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-434Unrestricted Upload of File with Dangerous Type
T1505.003Server Software Component: Web Shell

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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