CVE-2026-23967
Published: 22 January 2026
Summary
CVE-2026-23967 is a high-severity Improper Verification of Cryptographic Signature (CWE-347) vulnerability in Juneandgreen Sm-Crypto. Its CVSS base score is 7.5 (High).
Operationally, ranked at the 1.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Requires verification of digital signatures using organization-approved certificates before installation, directly preventing improper verification of cryptographic signatures.
Component authenticity commonly depends on cryptographic signatures; the control enforces proper verification of those signatures.
PKI certificates under an approved policy require cryptographic signature verification on issuance and validation.
Requires cryptographic signatures on authoritative data and support for verifying the chain of trust.
Mandates verification of cryptographic signatures (e.g., DNSSEC RRSIG) on resolution responses, addressing missing or bypassed signature checks.
Integrity tools commonly rely on cryptographic signatures whose improper validation this weakness covers.
Authenticity validation commonly relies on cryptographic signature or certificate checks that this control enforces.
MITRE ATT&CK Enterprise TechniquesAI
Insufficient information to map techniques.NVD Description
sm-crypto provides JavaScript implementations of the Chinese cryptographic algorithms SM2, SM3, and SM4. A signature malleability vulnerability exists in the SM2 signature verification logic of the sm-crypto library prior to version 0.3.14. An attacker can derive a new valid signature…
more
for a previously signed message from an existing signature. Version 0.3.14 patches the issue.
Deeper analysisAI
CVE-2026-23967 is a signature malleability vulnerability in the SM2 signature verification logic of the sm-crypto JavaScript library, which implements the Chinese cryptographic algorithms SM2, SM3, and SM4. The issue affects versions of sm-crypto prior to 0.3.14, allowing an attacker to derive a new valid signature for a previously signed message from an existing one. It is rated with a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N) and maps to CWE-347 (Improper Verification of Cryptographic Signature).
Any remote attacker can exploit this vulnerability without privileges or user interaction over the network with low complexity. By obtaining a valid SM2 signature for a message, the attacker can malleate it to produce another valid signature for the same message, potentially enabling signature forgery in applications relying on sm-crypto for SM2 verification. This leads to high integrity impact, undermining the non-repudiation properties of signatures.
The GitHub security advisory at https://github.com/JuneAndGreen/sm-crypto/security/advisories/GHSA-qv7w-v773-3xqm details the vulnerability, confirming that upgrading to version 0.3.14 of sm-crypto patches the issue by addressing the malleability flaw in the SM2 verification logic. Security practitioners should audit dependencies for vulnerable sm-crypto versions and apply the update promptly.
Details
- CWE(s)