thttpd 2007 has buffer underflow.
The htpasswd implementation of minihttpd before v1.28 and of thttpd before v2.28 is affected by a buffer overflow that can be exploited remotely to perform code execution.
Buffer overflow in defang in libhttpd.c for thttpd 2.21 to 2.23b1 allows remote attackers to execute arbitrary code via requests that contain '<' or '>' characters, which trigger the overflow when the characters are expanded to "<" and ">" sequences.
Off-by-one buffer overflow in Basic Authentication in Acme Labs thttpd 1.95 through 2.20 allows remote attackers to cause a denial of service and possibly execute arbitrary code.
Acme Thttpd Secure Webserver before 2.22, with the chroot option enabled, allows remote attackers to view sensitive files under the document root (such as .htpasswd) via a GET request with a trailing /.