CVE-2026-92591: craftcms cms Failing Open

Vulnerability summary

CVE-2026-92591 is a high (CVSS 8.2) Failing Open vulnerability in craftcms cms. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 33.7% of scored vulnerabilities.

Timeline

1. 16-09-2026
   PublishedVulnerability first disclosed.
2. 17-09-2026
   Last modifiedVulnerability information updated.

Description

Craft CMS 5.0.0 through 5.10.12 treats a database connection failure as meaning that Craft is not installed, which makes anonymous installer actions — including install/validate-site — reachable on an installed production site whenever PHP remains available but the configured MySQL endpoint does not. The action accepts a site name, serializes it through Site::getName(), and expands ${NAME} expressions using App::env(). An unauthenticated attacker who obtained a guest session cookie and matching CSRF token before the outage and whose session remains valid during it can submit a predictable variable name (for example Craft's conventional CRAFT_SECURITY_KEY) and receive its value, disclosing Craft secrets, process environment variables, $_SERVER entries, or PHP constants such as the security key, database credentials, or API keys. The issue requires an independently occurring database outage; the vulnerability itself provides no way to induce it. Fixed in 5.10.13.

• CWE-636Not Failing Securely ('Failing Open')When the product encounters an error condition or failure, its design requires it to fall back to a state that is less secure than other options that are available, such as selecting the weakest encryption algorithm or using the most permissive access control restrictions.