int EVP_CipherUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
                     const unsigned char *in, int inl)
{
    if (ctx->encrypt)
        return EVP_EncryptUpdate(ctx, out, outl, in, inl);
    else
        return EVP_DecryptUpdate(ctx, out, outl, in, inl);
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.