Vulnerability details
CVE-2026-70554
MaxSite CMS
MaxSite CMS Unauthenticated PHP Object Injection via maxsite_comuser Cookie
CVSS 4.0
9.3Critical
Official 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 scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.3Critical | 4.0 | CVEProject cvelistV5 (CNA) (VulnCheck) | 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 |
| 9.8Critical | 3.1 | CVEProject cvelistV5 (CNA) (VulnCheck) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| MaxSite | MaxSite CMS | 0.78 ≤ v ≤ 109.5 | CVEProject cvelistV5 (CNA) |
References and advisories
3
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Details
- Published
- 2026-08-04
- Last updated
- 2026-09-24
- State
- Published
- Assigner (CNA)
- VulnCheck
Exploit prediction (EPSS)
1.23%
Probability of exploitation in 30 days
69.1%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- None
- Technical impact
- Total
Weaknesses (CWE)
- CWE-502Deserialization of Untrusted Data