Out-of-bounds heap read during SM2/SM3 certificate signature verification. When parsing a certificate with an SM3wSM2 signature, the Subject Key Identifier computation reads the trailing 65 bytes of the public key without checking that the key is at least that long. A public key shorter than 65 bytes results in an out-of-bounds heap read, leading to a potential crash (denial of service); there is no out-of-bounds write. Note this only affects builds with SM2 support (--enable-sm2 or --enable-all).
{
"cna_assigner": "wolfSSL",
"cwe_ids": [
"CWE-125"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/12xxx/CVE-2026-12340.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "5.6.4"
},
{
"last_affected": "5.9.1"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"cpe": "cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "5.6.4"
},
{
"fixed": "5.9.2"
}
],
"source": "CPE_RANGE"
}
]
}