Heap-based buffer overflow in the ask_outfile_name function in openfile.c for GnuPG (gpg) 1.4 and 2.0, when running interactively, might allow attackers to execute arbitrary code via messages with "C-escape" expansions, which cause the make_printable_string function to return a longer string than expected while constructing a prompt.

Integer overflow in parse_comment in GnuPG (gpg) 1.4.4 allows remote attackers to cause a denial of service (segmentation fault) via a crafted message.

parse-packet.c in GnuPG (gpg) 1.4.3 and 1.9.20, and earlier versions, allows remote attackers to cause a denial of service (gpg crash) and possibly overwrite memory via a message packet with a large length (long user ID string), which could lead to an integer overflow, as demonstrated using the --no-armor option.

The integrity check feature in OpenPGP, when handling a message that was encrypted using cipher feedback (CFB) mode, allows remote attackers to recover part of the plaintext via a chosen-ciphertext attack when the first 2 bytes of a message block are known, and an oracle or other mechanism is available to determine whether an integrity check failed.