CVE-2021-3745Network attack vector

Authenticated dangerous file upload via gallery handler

Published Oct 28, 2021 · Updated Aug 3, 2024

Unrestricted file upload in flatCore CMS 2.1.0 and earlier allows remote authenticated users to place dangerous files through the gallery. The acp/core/files.upload_gallery.php handler derives the destination suffix from the client-supplied filename and moves the file into a web content directory without checking the configured image-extension allowlist. Administrator access is required, and the original upload is deleted after thumbnail processing, so exploitation depends on reaching the temporary file during processing.

CVSS severity6.6
Medium
EPSS probability1.11%
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 flatCore CMS 2.1.0 and earlier allows remote authenticated users to place dangerous files through the gallery. The acp/core/files.upload_gallery.php handler derives the destination suffix from the client-supplied filename and moves the file into a web content directory without checking the configured image-extension allowlist. Administrator access is required, and the original upload is deleted after thumbnail processing, so exploitation depends on reaching the temporary file during processing.

The record

CVE
CVE-2021-3745
Published
Oct 28, 2021
Updated
Aug 3, 2024
Vendor
flatCore
Product
flatCore CMS
Classifications
CWE-434, T1190
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Oct 28, 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=unspecified <=2.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

flatCore · flatCore CMSversion=unspecified <=2.1.0

Published CVSS scores

8.0@huntrdevCVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
6.0NVDAV:N/AC:M/Au:S/C:P/I:P/A:P
6.6NVDCVSS:3.1/AV:N/AC:H/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.

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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