Mojolicious versions from 4.59 before 9.48 for Perl expose a stable representation of the session CSRF token to a BREACH compression oracle.

csrftoken generates and caches one token per session and returns the same value on every call, and csrffield places that value in a hidden csrftoken input. When a response carrying the token also echoes attacker-controlled input and is gzip-compressed, the chosen values and the resulting compressed lengths form a BREACH oracle.

An attacker able to query it can recover the token and pass csrfprotect validation.

Mojolicious versions from 7.28 through 9.45 for Perl will generate weak HMAC session cookie secrets via "mojo generate app" by default.

When creating a default app skeleton with the "mojo generate app" tool, a weak secret is written to the application's configuration file using the insecure rand() function, and used for authenticating and protecting the integrity of the application's sessions. This may allow an attacker to brute force the application's session keys.

Release 9.46 fixes the issue by providing high quality randomness, even in absence of CryptX.

Users should be aware that the update does not replace previously generated weak secrets. A secret generated with the previous version MUST be replaced to ensure the updated version is using a strong secret.

The Mojolicious module before 8.65 for Perl is vulnerable to securecompare timing attacks that allow an attacker to guess the length of a secret string. Only versions after 1.74 are affected.