What is CVE-2026-73567?

CVE-2026-73567 is a critical-severity vulnerability in Juneandgreen Sm-Crypto, classified under Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG). CVSS score: 9.1/10. Published 2026-08-13.

How severe is CVE-2026-73567?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Vulnerability in Juneandgreen Sm-Crypto

CVE-2026-73567

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 v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

Affected products

Juneandgreen Sm-crypto — versions < 0.5.0

Weakness classification (CWE)

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

References

security-advisories@github.com (x_refsource_CONFIRM)
security-advisories@github.com (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-73567?: CVE-2026-73567 is a critical-severity vulnerability in Juneandgreen Sm-Crypto, classified under Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG). CVSS score: 9.1/10. Published 2026-08-13.
How severe is CVE-2026-73567?: Critical severity. CVSS v3 base score is 9.1 out of 10.