FreeBSD: VID-7695b0af-958f-11ec-9aa3-4ccc6adda413 (CVE-2021-40530): cryptopp -- ElGamal implementation allows plaintext recovery

The ElGamal implementation in Crypto++ through 8.5 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.