MaxSite CMS contains a PHP object injection vulnerability that allows unauthenticated attackers to execute arbitrary code by passing attacker-controlled serialized data in the maxsite_comuser cookie directly to unserialize() without validation or class allowlisting. Attackers can craft a malicious serialized PHP object payload delivered in a single HTTP request to trigger magic methods during object graph reconstruction, enabling property-oriented programming attacks or remote code execution via available gadget chains such as those targeting SoapClient or Imagick extensions.
History

Fri, 14 Aug 2026 17:15:00 +0000

Type Values Removed Values Added
First Time appeared Max-3000
Max-3000 maxsite Cms
CPEs cpe:2.3:a:max-3000:maxsite_cms:*:*:*:*:*:*:*:*
Vendors & Products Max-3000
Max-3000 maxsite Cms

Wed, 05 Aug 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Tue, 04 Aug 2026 21:45:00 +0000

Type Values Removed Values Added
First Time appeared Maxsite
Maxsite maxsite Cms
Vendors & Products Maxsite
Maxsite maxsite Cms

Tue, 04 Aug 2026 20:45:00 +0000

Type Values Removed Values Added
Description MaxSite CMS contains a PHP object injection vulnerability that allows unauthenticated attackers to execute arbitrary code by passing attacker-controlled serialized data in the maxsite_comuser cookie directly to unserialize() without validation or class allowlisting. Attackers can craft a malicious serialized PHP object payload delivered in a single HTTP request to trigger magic methods during object graph reconstruction, enabling property-oriented programming attacks or remote code execution via available gadget chains such as those targeting SoapClient or Imagick extensions.
Title MaxSite CMS Unauthenticated PHP Object Injection via maxsite_comuser Cookie
Weaknesses CWE-502
References
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-08-04T20:11:55.735Z

Updated: 2026-08-14T16:51:28.249Z

Reserved: 2026-08-04T19:19:05.906Z

Link: CVE-2026-70554

cve-icon Vulnrichment

Updated: 2026-08-05T13:52:53.132Z

cve-icon NVD

Status : Received

Published: 2026-08-04T21:16:38.613

Modified: 2026-08-05T15:17:13.783

Link: CVE-2026-70554

cve-icon Redhat

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