CVE-2026-87930

9.2 CRITICAL 0.6% exploit odds No fix listed Code execution Web app

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.6% chance of exploitation in the next 30 days (EPSS).
Fix: No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

2026-09-09 16:12 UTC ReservedThe CVE id was reserved by its CNA
2026-09-09 17:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-09-09 20:14 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.6% in the next 30 days (EPSS).
Severity: 9.2 CRITICAL (CVSS).
Fix: none linked yet, which raises it.

Details

Published: 2026-09-09 17:17 UTC
Last modified: 2026-09-09 20:14 UTC
Exploit probability: 0.6% · EPSS, next 30 days
Weakness: CWE-502 · Unsafe deserialization
Record status: Deferred

Attack profile CVSS 4.0 · 9.2

Attack vector: Network
Complexity: Low
Attack requirements: Present
Privileges needed: None
User interaction: None
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-87930.md and follow it. Check whether this project is affected by CVE-2026-87930. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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References

NVD record · CVE.org record