CVE-2026-115938: Low privilege condition filter escapes Twig sandbox, recovers "securityKey" and reaches RCE
Craft CMS allows any authenticated control panel user to submit an element-search condition whose element selector is evaluated as a sandboxed Twig object template. Craft’s allowed column filter delegates property lookup to Yii ArrayHelper, outside Twig’s SecurityPolicy. Repeated single-segment lookups therefore bypass the sandbox’s empty property/method allowlists.
The vulnerable condition value is ultimately cast to an integer. That does not protect the secret: the template can return author ID 1 when a guessed key character is correct and an impossible ID otherwise. The JSON endpoint returns entries for the first case and an empty array for the second, forming a stable remote character oracle.
After recovering GeneralConfig::securityKey, the same user can compute Craft’s generic HMAC wire format offline. Signed parameters such as redirect are then accepted and passed to unsandboxed View::renderObjectTemplate(), where Twig’s string-callable form can invoke native PHP callables. The regression proof uses the harmless substr() callback and observes abcdef becoming cdef; it does not execute an OS command.
Affected Software
Event History
Frequently Asked Questions
What level of access does an attacker need?
An attacker needs an authenticated Craft CMS control panel account. The issue is reachable by any authenticated control panel user through an element-search condition.
Does the integer conversion of the condition value prevent secret recovery?
No. The attacker can use the endpoint's differing JSON responses to distinguish a valid author ID from an impossible one, creating a character-by-character oracle for recovering the securityKey.
Was OS command execution demonstrated in the regression proof?
No. The proof invoked the harmless native substr() callback and observed abcdef become cdef; it did not execute an OS command.