Deserialization in Maxsite Cms
CVE-2026-87930
MaxSite CMS through 109.6 passes the ci_session cookie to unserialize() without class restrictions, allowing unauthenticated attackers to inject PHP objects. Attackers can forge valid session cookies using the hardcoded encryption key to trigger magic methods and corrupt application state or achieve code execution if gadget classes exist.
Vulnerability class: Insecure Deserialization
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
Weakness classification (CWE)
References
- disclosure@vulncheck.com (product)
- disclosure@vulncheck.com (technical-description, exploit)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-87930?
- CVE-2026-87930 is a high-severity vulnerability in Maxsite Cms, classified under Deserialization of Untrusted Data. CVSS score: 8.1/10. Published 2026-09-09.
- How severe is CVE-2026-87930?
- High severity. CVSS v3 base score is 8.1 out of 10.