CVE-2026-87930 MaxSite CMS through 109.6 PHP Object Injection via ci_session
Unauthenticated attackers can achieve code execution or corrupt state in MaxSite CMS by injecting PHP objects via forged session cookies using a hardcoded key.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-87930?
CVE-2026-87930 is a critical unsafe deserialization vulnerability in MaxSite CMS, published on 9 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-502
Which versions are affected by CVE-2026-87930?
How do I fix CVE-2026-87930?
No fix has been published for CVE-2026-87930 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-87930 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-87930 exists.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-2phq-cm26-22pm.