LTI 1.3 Tool Library is a library used for building IMS-certified LTI 1.3 tool providers in PHP. Prior to version 5.0, the function used to generate random nonces was not sufficiently cryptographically complex. Users should upgrade to version 5.0 to receive a patch. There are currently no known workarounds.
https://github.com/packbackbooks/lti-1-3-php-library/security/advisories/GHSA-768m-5w34-2xf5