In LibTomCrypt through 1.18.2, the derdecodeutf8string function (in derdecodeutf8string.c) does not properly detect certain invalid UTF-8 sequences. This allows context-dependent attackers to cause a denial of service (out-of-bounds read and crash) or read information from other memory locations via carefully crafted DER-encoded data.

The endCoinFlip function and throwSlammer function of the smart contract implementations for Cryptogs, an Ethereum game, generate random numbers with an old block's hash. Therefore, attackers can predict the random number and always win the game.