In Pure-FTPd before 1.0.50, an incorrect max_filesize quota mechanism in the server allows attackers to upload files of unbounded size, which may lead to denial of service or a server hang. This occurs because a certain greater-than-zero test does not anticipate an initial -1 value. (Versions 1.0.23 through 1.0.49 are affected.)

An issue was discovered in Pure-FTPd 1.0.49. An uninitialized pointer vulnerability has been detected in the diraliases linked list. When the *lookup_alias(const char alias) or print_aliases(void) function is called, they fail to correctly detect the end of the linked list and try to access a non-existent list member. This is related to init_aliases in diraliases.c.

The glob implementation in Pure-FTPd before 1.0.32, and in libc in NetBSD 5.1, does not properly expand expressions containing curly brackets, which allows remote authenticated users to cause a denial of service (memory consumption) via a crafted FTP STAT command.

The STARTTLS implementation in ftp_parser.c in Pure-FTPd before 1.0.30 does not properly restrict I/O buffering, which allows man-in-the-middle attackers to insert commands into encrypted FTP sessions by sending a cleartext command that is processed after TLS is in place, related to a "plaintext command injection" attack, a similar issue to CVE-2011-0411.