Vulnerability 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.
CVSS Score
CRITICAL
Related Weaknesses (CWE)
References
- https://github.com/maxsite/cms
- https://max-3000.com/page/maxsite-cms-109-6
- https://www.vulncheck.com/advisories/maxsite-cms-unauthenticated-php-object-inje
FAQ
What is CVE-2026-70554?
CVE-2026-70554 is a vulnerability with a CVSS score of 9.8 (CRITICAL). 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 d...
How severe is CVE-2026-70554?
CVE-2026-70554 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-70554?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.