CVE-2026-73567Public exploitNetwork attack vector

Private-key recovery via predictable SM2 random generation

Published Aug 13, 2026 · Updated Aug 13, 2026

Weak PRNG use in sm-crypto before 0.5.0 allows remote attackers to recover SM2 private keys and forge signatures in Node.js. The module-wide SecureRandom instance in src/sm2/utils.js delegates to jsbn, whose Node.js fallback seeds ARC4 with Math.random() values and wall-clock time instead of globalThis.crypto. Exploitation requires observation of the process's Math.random() outputs and an estimate of key-generation time; successful prediction exposes private keys and signing ephemeral scalars.

CVSS severity9.1
Critical
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak PRNG use in sm-crypto before 0.5.0 allows remote attackers to recover SM2 private keys and forge signatures in Node.js. The module-wide SecureRandom instance in src/sm2/utils.js delegates to jsbn, whose Node.js fallback seeds ARC4 with Math.random() values and wall-clock time instead of globalThis.crypto. Exploitation requires observation of the process's Math.random() outputs and an estimate of key-generation time; successful prediction exposes private keys and signing ephemeral scalars.

The record

CVE
CVE-2026-73567
Published
Aug 13, 2026
Updated
Aug 13, 2026
Vendor
JuneAndGreen
Product
sm-crypto
Classifications
CWE-338, T1552.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

JuneAndGreen · sm-cryptoversion=< 0.5.0

Published CVSS scores

9.1GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-338Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
T1552.004Unsecured Credentials: Private Keys

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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