Cygwin versions 1.7.2 up to and including 1.8.0 are vulnerable to buffer overflow vulnerability in wcsxfrm/wcsxfrm_l functions resulting into denial-of-service by crashing the process or potential hijack of the process running with administrative privileges triggered by specially crafted input string.

Cygwin before 2.5.0 does not properly handle updating permissions when changing users, which allows attackers to gain privileges.

setup.exe before 2.573.2.3 in Cygwin does not properly verify the authenticity of packages, which allows remote Cygwin mirror servers or man-in-the-middle attackers to execute arbitrary code via a package list containing the MD5 checksum of a Trojan horse package.

Heap-based buffer overflow in cygwin1.dll in Cygwin 1.5.7 and earlier allows context-dependent attackers to execute arbitrary code via a filename with a certain length, as demonstrated by a remote authenticated user who uses the SCP protocol to send a file to the Cygwin machine, and thereby causes scp.exe on this machine to execute, and then overwrite heap memory with characters from the filename. NOTE: it is also reported that a related issue might exist in 1.5.7 through 1.5.19.