CVE-2026-73567 JuneAndGreen CVE debrief

Who should care

Developers and administrators using sm-crypto versions prior to 0.5.0 for cryptographic operations should assess exposure and upgrade to version 0.5.0 or later. This includes teams responsible for maintaining systems that rely on sm-crypto for secure communication, as well as security teams that need to verify the integrity of cryptographic operations within their environments.

Why it matters

The sm-crypto library's predictable key generation allows an attacker to recover SM2 private keys and forge signatures, impacting cryptographic operations.

• Recovery of SM2 private keys by an attacker
• Forgery of signatures using predicted ephemeral scalars
• Potential compromise of cryptographic operations
• Verification priority for systems using sm-crypto versions prior to 0.5.0

Technical summary

The sm-crypto library's default key generation path in Node.js used a predictable seed for the SecureRandom instance, supplied by [email protected], which seeds an ARC4 stream from Math.random() and new Date().getTime(). An attacker who can observe the process's Math.random() outputs and estimate the key-generation time can reconstruct the seed, recover generated SM2 private keys, and predict signing ephemeral scalars used to forge signatures. This issue is fixed in version 0.5.0, which changes the key generation path to use a more secure random number generator.

Defensive priority

High priority for systems using sm-crypto versions prior to 0.5.0 for cryptographic operations

Recommended defensive actions

• Upgrade to sm-crypto version 0.5.0 or later
• Review and update cryptographic key generation and usage in systems using sm-crypto
• Monitor for potential exploitation attempts
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The vulnerability was reported and fixed in version 0.5.0 of the sm-crypto library. The issue involves the use of Math.random() and new Date().getTime() to seed the SecureRandom instance, which can be predictable. This weakness allows an attacker to recover SM2 private keys and forge signatures, impacting cryptographic operations. Defenders should verify system configurations, review key generation practices, and monitor for potential exploitation attempts.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.