CVE-2018-6829

cipher/elgamal.c in Libgcrypt through 1.8.2, when used to encrypt messages directly, improperly encodes plaintexts, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for Libgcrypt's ElGamal implementation.

• libgcrypt20 (unimportant)
• libgcrypt11 (unimportant)
• gnupg1 (unimportant)
• gnupg (unimportant) https://github.com/weikengchen/attack-on-libgcrypt-elgamal https://github.com/weikengchen/attack-on-libgcrypt-elgamal/wiki https://lists.gnupg.org/pipermail/gcrypt-devel/2018-February/004394.html GnuPG uses ElGamal in hybrid mode only. This is not a vulnerability in libgcrypt, but in an application using it in an insecure manner, see also https://lists.gnupg.org/pipermail/gcrypt-devel/2018-February/004401.html