CVE-2026-92591: Craft CMS 5.0.0 before 5.10.13 Environment Secret Exposure via Installer

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-16 · updated 2026-09-22
Weakness: CWE-636

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.

Affected products

craftcms cms: from 5.0.0 before 5.10.13 — fixed in 5.10.13

How to fix

Upgrade to a fixed version: craftcms cms 5.10.13. Check the vendor advisory for mitigations.

References

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