Vulnerability details

CVE-2026-73567

JuneAndGreen sm-crypto

sm-crypto: Predictable SM2 key generation in Node.js: default RNG uses Math.random + wall clock

CVSS 3.1

9.1Critical

Official description

sm-crypto provides JavaScript implementations of the Chinese cryptographic algorithms SM2, SM3, and SM4. Prior to 0.5.0, the default no-argument sm2.generateKeyPairHex() path in Node.js uses the module-wide SecureRandom instance in src/sm2/utils.js, supplied by jsbn@1.1.0, which seeds an ARC4 stream from Math.random() and new Date().getTime() because window.crypto.getRandomValues is unavailable even though globalThis.crypto exists. 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.

CVSS scores

Score	Version	Source	Vector
9.1Critical	3.1	CVEProject cvelistV5 (CNA) (GitHub_M)	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`

Affected products

Vendor	Product	Versions	Source
JuneAndGreen	sm-crypto	< 0.5.0	CVEProject cvelistV5 (CNA)

References and advisories

https://github.com/JuneAndGreen/sm-crypto/security/advisories/GHSA-vh45-f885-3848 x_refsource_CONFIRM
https://github.com/JuneAndGreen/sm-crypto/commit/1f9bd7bd160c24efd9c26c8f7fda997c68c823d0 x_refsource_MISC

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Details

Published: 2026-08-13
Last updated: 2026-08-14
State: Published
Assigner (CNA): GitHub_M

Exploit prediction (EPSS)

0.44%

Probability of exploitation in 30 days

38.7%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: Yes
Exploitation: None
Technical impact: Total

Weaknesses (CWE)

CWE-338
Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)