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.)

In Pure-FTPd 1.0.49, a stack exhaustion issue was discovered in the listdir function in ls.c.

Pure-FTPd 1.0.48 allows remote attackers to prevent legitimate server use by making enough connections to exceed the connection limit.