The timing attack protection in Rijndael::Enc::ProcessAndXorBlock and Rijndael::Dec::ProcessAndXorBlock in Crypto++ (aka cryptopp) before 5.6.4 may be optimized out by the compiler, which allows attackers to conduct timing attacks.

Crypto++ (aka cryptopp) through 5.6.4 does not document the requirement for a compile-time NDEBUG definition disabling the many assert calls that are unintended in production use, which might allow context-dependent attackers to obtain sensitive information by leveraging access to process memory after an assertion failure, as demonstrated by reading a core dump.

Crypto++ (aka cryptopp) through 5.6.5 contains an out-of-bounds read vulnerability in zinflate.cpp in the Inflator filter.