CVE-2026-12340: Out-of-bounds heap read in SM2/SM3 certificate Subject Key Identifier computation
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).
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2026-12340?
The severity of CVE-2026-12340 is rated as medium with a CVSS score of 6.3.
How do I fix CVE-2026-12340?
To fix CVE-2026-12340, you should apply the available patches provided by the software maintainers.
What software is affected by CVE-2026-12340?
CVE-2026-12340 affects the OpenSSL and wolfSSL software libraries.
What type of vulnerability is CVE-2026-12340?
CVE-2026-12340 is an out-of-bounds heap read vulnerability related to SM2/SM3 certificate signature verification.
What is the risk associated with CVE-2026-12340?
CVE-2026-12340 has a risk rating of 43, indicating potential security concerns that should be addressed promptly.