CVE-2025-12346Public exploitNetwork attack vector

Authenticated web-shell upload via header-controlled file path

Published Oct 28, 2025 · Updated Oct 28, 2025

Unrestricted file upload in MaxSite CMS 109 and earlier allows remote authenticated users to write files beneath the web root via HTTP headers. The uploads-require-maxsite.php handler concatenates attacker-controlled upload-directory and filename headers with the web root and writes the raw POST body without restricting file type or destination. Backend authentication is required; overwriting the uploads .htaccess file first permits a subsequent PHP upload to execute as a web shell.

CVSS severity8.8
High
EPSS probability0.36%
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 MaxSite CMS 109 and earlier allows remote authenticated users to write files beneath the web root via HTTP headers. The uploads-require-maxsite.php handler concatenates attacker-controlled upload-directory and filename headers with the web root and writes the raw POST body without restricting file type or destination. Backend authentication is required; overwriting the uploads .htaccess file first permits a subsequent PHP upload to execute as a web shell.

The record

CVE
CVE-2025-12346
Published
Oct 28, 2025
Updated
Oct 28, 2025
Vendor
MaxSite
Product
MaxSite CMS
Classifications
CWE-434, CWE-284, T1505.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 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=109

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

MaxSite · MaxSite CMSversion=109

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.5VulDBAV:N/AC:L/Au:S/C:P/I:P/A:P
5.3VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
6.3VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
2.1VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E: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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
CWE-284Improper Access Control
T1505.003Server Software Component Web 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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