CVE-2026-12340 | Out-of-bounds heap read during SM2/SM3 certificate signature… | CVSS 6.3 MEDIUM

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).

Metadata

CVE ID: CVE-2026-12340
State: PUBLISHED
Assigner: wolfSSL
Reserved: 2026-06-15 16:30 UTC
Published: 2026-06-25 19:36 UTC
Last updated: 2026-06-25 19:36 UTC
Primary CWE: CWE-125
CWE-125 Out-of-bounds Read
Vendor / Product: wolfSSL / wolfSSL
Sources: cve.org · NVD

Severity & Metrics

6.3 MEDIUM CVSS 4.0

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

Affected products (1)

Vendor	Product	Platform	Versions
wolfSSL	wolfSSL	—	5.6.4 ≤ 5.9.1

Weakness (CWE)

CWE	Source	Description
CWE-125	cna	CWE-125 Out-of-bounds Read

CVSS scores (1)

Score	Severity	Version	Source	Vector
6.3	MEDIUM	4.0	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

References (2)