Vulnerability Description
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).
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Wolfssl | Wolfssl | >= 5.6.4, < 5.9.2 |
Related Weaknesses (CWE)
References
- https://github.com/wolfSSL/wolfssl/pull/10641Issue TrackingPatch
- https://www.wolfssl.com/docs/security-vulnerabilities/Vendor Advisory
FAQ
What is CVE-2026-12340?
CVE-2026-12340 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 t...
How severe is CVE-2026-12340?
CVE-2026-12340 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-12340?
Check the references section above for vendor advisories and patch information. Affected products include: Wolfssl Wolfssl.