# CVE-2026-73567: sm-crypto: Predictable SM2 key generation in Node.js: default RNG uses Math.random + wall clock

> Attackers can recover SM2 private keys and forge signatures due to predictable random number generation in the sm-crypto library.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 Aug 2026
- **Updated:** 14 Aug 2026
- **Also known as:** GHSA-vh45-f885-3848

## What is CVE-2026-73567?

CVE-2026-73567 is a critical vulnerability in JuneAndGreen sm-crypto, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### 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.

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

## Which versions are affected by CVE-2026-73567?

2 open source packages ship an affected version, including sm-crypto.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `sm-crypto` | npm | All versions | 0.5.0 |
| `sm-crypto` | npm | All versions | 0.5.0 |

## How do I fix CVE-2026-73567?

Upgrade sm-crypto to 0.5.0 or later.

## Is CVE-2026-73567 being exploited?

There is no known exploitation of CVE-2026-73567 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-73567 and fix it if it is affected.

What it is: CVE-2026-73567 is a critical vulnerability in JuneAndGreen sm-crypto, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-73567 in the wild and no public exploit code.

Affected packages and fixed versions:
- sm-crypto (npm): affected all versions; fixed in 0.5.0
- sm-crypto (npm): affected all versions; fixed in 0.5.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-73567/ (Markdown: https://insights.sbomify.com/CVE-2026-73567/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-73567
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-73567
- OSV: https://osv.dev/vulnerability/CVE-2026-73567

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-73567/
Summaries are generated and may contain mistakes; the official description above is the record.