CVE-2019-11366

An issue was discovered in atftpd in atftp 0.7.1. It does not lock the
thread_list_mutex mutex before assigning the current thread data structure.
As a result, the daemon is vulnerable to a denial of service attack due to
a NULL pointer dereference. If thread_data is NULL when assigned to
current, and modified by another thread before a certain tftpd_list.c
check, there is a crash when dereferencing current->next.

Bugs

• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=927553&gt;