Vulnerability · Published Aug 13, 2026 · Assigned by GitHub_M
CVE-2026-73567sm-crypto: Predictable SM2 key generation in Node.js: default RNG uses Math.random + wall clock
Critical 9.1
In plain English
A critical-severity security flaw in sm-crypto from JuneAndGreen. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | sm-crypto | 0.5.0 | GHSA-vh45-f885-3848 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| JuneAndGreen | sm-crypto | < 0.5.0 |
Weakness: CWE-338 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N