VulnerabilityPublished 13 Aug 2026Updated 14 Aug 2026

CVE-2026-73567: JuneAndGreen sm-crypto · PRNG

Affects JuneAndGreen sm-cryptoSource CVE Database V5

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Not known to be exploited · CVSS 9.1 Critical : upgrade to 0.5.0 as a priority.

Data as of 10 Nov 2026, 23:24 UTC

CVSS 3.1 base score

9.1Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.5.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade JuneAndGreen sm-crypto to 0.5.0.

Affected software

Product	Affected	Fixed in
JuneAndGreensm-crypto	Affected <0.5.0	Fixed in 0.5.0
npmsm-crypto`pkg:npm/sm-crypto`Other threats	Affected <0.5.0	Fixed in 0.5.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade to sm-crypto version 0.5.0 or later, where this issue is fixed by using a secure random number generator. No other mitigations are indicated.

Description

The sm-crypto JavaScript library for Chinese cryptographic algorithms SM2, SM3, and SM4 has a critical vulnerability in versions prior to 0.5.0. The default key generation in Node.js uses a cryptographically weak pseudo-random number generator seeded from Math.random() and the current time, allowing attackers who can observe Math.random() outputs and estimate key generation time to recover private keys and forge signatures. This issue is fixed in version 0.5.0.

Impact

An attacker capable of observing the process's Math.random() outputs and estimating the key generation time can reconstruct the seed used for key generation, recover SM2 private keys, and predict ephemeral signing scalars. This compromises the confidentiality of private keys and the integrity of digital signatures, allowing signature forgery. There is no indication of active exploitation in the wild.

Summary

sm-crypto versions before 0.5.0 use a module-wide SecureRandom instance seeded by an ARC4 stream derived from Math.random() and new Date().getTime() due to the unavailability of window.crypto.getRandomValues in Node.js, despite globalThis.crypto existing. This weak seeding method allows attackers who can observe Math.random() outputs and approximate the key generation time to reconstruct the seed, recover SM2 private keys, and predict ephemeral signing scalars, enabling signature forgery. The vulnerability is identified as CWE-338 (Use of Cryptographically Weak PRNG). It is fixed in version 0.5.0.

CWE-338Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) (opens in a new tab)
Base weaknessLikelihood of exploit: MediumOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.
Implementation
Use functions or hardware which use a hardware-based random number generation for all crypto. This is the recommended solution. Use CyptGenRandom on Windows, or hw_rand() on Linux.
OWASP Cheat Sheets
Transport Layer Protection (opens in a new tab)
User Privacy Protection (opens in a new tab)
Password Storage (opens in a new tab)
Cryptographic Storage (opens in a new tab)
HSTS (opens in a new tab)
OWASP ASVS 4.0.3
V6.3.3 (opens in a new tab)
V6.3.2 (opens in a new tab)
V6.3.1 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 21 Aug 2026, 13:31 UTC

WeaknessesCWE-338

Technical details

References

Community reviews

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