CVE-2026-12340
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk13th percentile — higher than 13% of all known CVEs
Summary
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).
Risk Assessment
An attacker can supply a specially crafted certificate with a short public key, causing a system crash and service disruption. This vulnerability only affects builds with SM2 support enabled.
Recommendation
Update the library to a version containing the fix that checks the public key length before reading. If not possible, disable SM2 support (--disable-sm2) in the build configuration.
Original NVD description (English source)
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).