CVE-2026-73567 JuneAndGreen CVE debrief

Who should care

Defenders responsible for Node.js environments using sm-crypto, especially those handling cryptographic key generation and management, should assess exposure and prioritize verification and remediation efforts.

Why it matters

CVE-2026-73567 is a critical vulnerability in sm-crypto's SM2 key pair generation, allowing attackers to recover private keys and forge signatures. Defenders should prioritize verifying exposure in Node.js environments using sm-crypto versions prior to 0.5.0 and assessing the effectiveness of their current cryptographic key generation and management practices.

• Recovery of SM2 private keys by attackers who can observe Math.random() outputs and estimate key-generation time
• Prediction of signing ephemeral scalars for forging signatures
• Potential for attackers to forge signatures using the recovered private keys and predicted ephemeral scalars
• Verification of exposure in Node.js environments using sm-crypto versions prior to 0.5.0

Technical summary

The sm-crypto library, used for implementing Chinese cryptographic algorithms, had a vulnerability in its SM2 key pair generation process. Prior to version 0.5.0, the default no-argument sm2.generateKeyPairHex() path in Node.js used a module-wide SecureRandom instance seeded from Math.random() and new Date().getTime(). This allowed attackers who could observe Math.random() outputs and estimate key-generation time to reconstruct the seed, recover generated SM2 private keys, and predict signing ephemeral scalars for forging signatures.

Defensive priority

Defenders should prioritize verifying exposure in Node.js environments using sm-crypto versions prior to 0.5.0 and assessing the effectiveness of their current cryptographic key generation and management practices.

Recommended defensive actions

• Verify if Node.js environments are using sm-crypto versions prior to 0.5.0
• Assess the effectiveness of current cryptographic key generation and management practices
• Upgrade sm-crypto to version 0.5.0 or later
• Review and update key generation and signing processes to ensure secure practices
• 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

Evidence notes

The CVE record and NVD entry provide details on the vulnerability in sm-crypto, including its critical CVSS score of 9.1 and the availability of a fix in version 0.5.0. The vulnerability is related to the use of Math.random() and new Date().getTime() for seeding the SecureRandom instance, which can be exploited by attackers to recover private keys and forge signatures. The evidence is based on the official CVE Program record and the NIST NVD detail page.

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.