url.cpp in libproxy through 0.4.15 is prone to a buffer overflow when PAC is enabled, as demonstrated by a large PAC file that is delivered without a Content-length header.

url::recvline in url.cpp in libproxy 0.4.x through 0.4.15 allows a remote HTTP server to trigger uncontrolled recursion via a response composed of an infinite stream that lacks a newline character. This leads to stack exhaustion.

Format string vulnerability in the print_proxies function in bin/proxy.c in libproxy 0.3.1 might allow context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via format string specifiers in a proxy name, as demonstrated using the http_proxy environment variable or a PAC file.

Stack-based buffer overflow in the url::get_pac function in url.cpp in libproxy 0.4.x before 0.4.9 allows remote servers to have an unspecified impact via a large proxy.pac file.

Heap-based buffer overflow in the px_pac_reload function in lib/pac.c in libproxy 0.2.x and 0.3.x allows remote servers to have an unspecified impact via a crafted Content-Length size in an HTTP response header for a proxy.pac file request, a different vulnerability than CVE-2012-4504.