Vulnerability Details CVE-2026-12340
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).
Exploit prediction scoring system (EPSS) score
EPSS Score 0.002
EPSS Ranking 13.3%
CVSS Severity
CVSS v3 Score 7.5
References
Products affected by CVE-2026-12340
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cpe:2.3:a:wolfssl:wolfssl:5.6.4
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cpe:2.3:a:wolfssl:wolfssl:5.6.6
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cpe:2.3:a:wolfssl:wolfssl:5.7.0
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cpe:2.3:a:wolfssl:wolfssl:5.7.2
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cpe:2.3:a:wolfssl:wolfssl:5.7.4
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cpe:2.3:a:wolfssl:wolfssl:5.7.6
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cpe:2.3:a:wolfssl:wolfssl:5.8.0
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cpe:2.3:a:wolfssl:wolfssl:5.8.2
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cpe:2.3:a:wolfssl:wolfssl:5.8.4