In Botan before 2.19.3, it is possible to forge OCSP responses due to a certificate verification error. This issue was introduced in Botan 1.11.34 (November 2016).

The ElGamal implementation in Botan through 2.18.1, as used in Thunderbird and other products, 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.