In Botan 1.8.0 through 1.11.33, when decoding BER data an integer overflow could occur, which would cause an incorrect length field to be computed. Some API callers may use the returned (incorrect and attacker controlled) length field in a way which later causes memory corruption or other failure.

The Miller-Rabin primality check in Botan before 1.10.8 and 1.11.x before 1.11.9 improperly uses a single random base, which makes it easier for remote attackers to defeat cryptographic protection mechanisms via a DH group.