CVE-2026-12340
Out-of-bounds heap read in SM2/SM3 certificate Subject Key Identifier computation
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).
INFO
Published Date :
June 25, 2026, 7:36 p.m.
Last Modified :
June 25, 2026, 7:36 p.m.
Remotely Exploit :
Yes !
Source :
wolfSSL
Affected Products
The following products are affected by CVE-2026-12340
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | 50d2cd11-d01a-48ed-9441-5bfce9d63b27 |
Solution
- Update to a version with SM2 support fixes.
- Ensure SM2 support is enabled.
- Verify certificate signature processing.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-12340 vulnerability anywhere in the article.