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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).

PUBLISHED Reserved 2026-06-15 | Published 2026-06-25 | Updated 2026-06-26 | Assigner wolfSSL




MEDIUM: 6.3CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Problem types

CWE-125 Out-of-bounds Read

Product status

Default status
unaffected

5.6.4 (semver)
affected

Credits

David Pokora, Trail of Bits (in collaboration with Anthropic) finder

References

github.com/wolfSSL/wolfssl/pull/10641 patch

www.wolfssl.com/docs/security-vulnerabilities/

cve.org (CVE-2026-12340)

nvd.nist.gov (CVE-2026-12340)

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