What’s Vulnerable › Vulnerabilities

CVE-2026-70553: MaxSite CMS Unauthenticated RCE via Install Endpoint

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-04 · updated 2026-10-24
• Weakness: CWE-94

Description

MaxSite CMS contains a remote code execution vulnerability that allows unauthenticated attackers to inject arbitrary PHP code into the application configuration file by submitting crafted POST requests to the install endpoint after installation is complete. Attackers can supply a malicious db_dbprefix value containing a single quote to break out of a PHP string literal in application/config/database.php, appending attacker-controlled PHP statements that are executed by the web server on every subsequent request, resulting in persistent unauthenticated remote code execution as the web-server process user.

Affected products

• MaxSite CMS: from 105.2 through 109.5

References

• https://github.com/maxsite/cms
• https://max-3000.com/page/maxsite-cms-109-6
• https://www.vulncheck.com/advisories/maxsite-cms-unauthenticated-rce-via-install-endpoint

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