gf2n.cpp in Crypto++ (aka cryptopp) through 8.9.0 allows attackers to cause a denial of service (application crash) via DER public-key data for an F(2^m) curve, if the degree of each term in the polynomial is not strictly decreasing.
Crypto++ 5.6.4 incorrectly uses Microsoft's stack-based _malloca and _freea functions. The library will request a block of memory to align a table in memory. If the table is later reallocated, then the wrong pointer could be freed.
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.