In the Linux kernel, the following vulnerability has been resolved: libceph: return the handler error from monhandleauthdone() Currently any error from cephauthhandlereplydone() is propagated via finishauth() but isn't returned from monhandleauthdone(). This results in higher layers learning that (despite the monitor considering us to be successfully authenticated) something went wrong in the authentication phase and reacting accordingly, but msgr2 still trying to proceed with establishing the session in the background. In the case of secure mode this can trigger a WARN in setupcrypto() and later lead to a NULL pointer dereference inside of prepareauthsignature().