MaxSite CMS Unauthenticated PHP Object Injection via maxsite_comuser Cookie
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.
CVE-2026-70554
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-70554
MaxSite CMS
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "MaxSite",
"product": "MaxSite CMS",
"versions": [
{
"status": "affected",
"version": "0.78",
"versionType": "custom",
"lessThanOrEqual": "109.5"
},
{
"status": "unaffected",
"version": "109.6",
"versionType": "custom"
}
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-70554
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #934 · Revision 1
- Added to Heist Feed
- Publisher date