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Medium 6.3Published Jun 25, 2026

CVE-2026-12340Out-of-bounds heap read in SM2/SM3 certificate Subject Key Identifier computation

Updated under an hour ago ()

Does this affect you?

It affects wolfSSL. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
6.3 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness (CWE)
CWE-125
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
wolfSSL
NVD analysis
Analyzed
Record last updated
Jun 26, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
wolfSSL wolfSSL
wolfssl:wolfssl (from the name)
from 5.6.4 through 5.9.1
CNA record
wolfssl wolfssl
wolfssl:wolfssl
from 5.6.4 before 5.9.2
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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