An out-of-bounds heap read vulnerability occurs during SM2/SM3 certificate signature verification when parsing certificates with an SM3wSM2 signature. The Subject Key Identifier computation reads 65 trailing bytes of the public key without verifying the key length, causing a heap read beyond the buffer if the key is shorter than 65 bytes. This can lead to a denial of service via application crash. The issue affects only builds with SM2 support enabled.