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sm-crypto Affected by Signature Forgery in SM2-DSA

High severity GitHub Reviewed Published Jan 20, 2026 in JuneAndGreen/sm-crypto • Updated Jan 21, 2026

Package

npm sm-crypto (npm)

Affected versions

< 0.4.0

Patched versions

0.4.0

Description

Summary

A signature forgery vulnerability exists in the SM2 signature verification logic of sm-crypto. Under default configurations, an attacker can forge valid signatures for arbitrary public keys. If the message space contains sufficient redundancy, the attacker can fix the prefix of the message associated with the forged signature to satisfy specific formatting requirements.

Credit

This vulnerability was discovered by:

  • XlabAI Team of Tencent Xuanwu Lab
  • Atuin Automated Vulnerability Discovery Engine

References

@JuneAndGreen JuneAndGreen published to JuneAndGreen/sm-crypto Jan 20, 2026
Published to the GitHub Advisory Database Jan 21, 2026
Reviewed Jan 21, 2026
Last updated Jan 21, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS score

Weaknesses

Improper Verification of Cryptographic Signature

The product does not verify, or incorrectly verifies, the cryptographic signature for data. Learn more on MITRE.

CVE ID

CVE-2026-23965

GHSA ID

GHSA-hpwg-xg7m-3p6m

Source code

Credits

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