In PHP versions 8.0.* before 8.0.29, 8.1.* before 8.1.20, 8.2.* before 8.2.7 when using SOAP HTTP Digest Authentication, random value generator was not checked for failure, and was using narrower range of values than it should have. In case of random generator failure, it could lead to a disclosure of 31 bits of uninitialized memory from the client to the server, and it also made easier to a malicious server to guess the client's nonce.
https://github.com/php/php-src/security/advisories/GHSA-76gg-c692-v2mw