VulnerabilityPublished 22 Jan 2026

CVE-2026-23966: JuneAndGreen sm-crypto · Insufficient Verification of Data Authenticity

Affects JuneAndGreen sm-cryptoSource CVE Database V5

Not known to be exploited · CVSS 9.1 Critical : upgrade to 0.3.14 as a priority.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

9.1Critical

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.3.14

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 22 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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 0.3.14.

Affected software

Product	Affected	Fixed in
JuneAndGreensm-crypto	Affected <0.3.14	Fixed in 0.3.14
npmsm-crypto`pkg:npm/sm-crypto`Other threats	Affected <0.3.14	Fixed in 0.3.14

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

AI-suggested

Immediately upgrade all instances of sm-crypto to version 0.3.14 or later to apply the patch that fixes the private key recovery vulnerability.
Conduct a thorough audit of all applications and services using sm-crypto to identify affected versions and usage contexts.
Replace or rotate any private keys that may have been exposed due to this vulnerability, especially if the vulnerable versions were in use in production environments.
Implement strict access controls and monitoring on cryptographic key usage to detect abnormal decryption request patterns that could indicate exploitation attempts.
Where possible, consider migrating to more widely vetted cryptographic libraries that implement SM2, SM3, and SM4 with proven security records.
Educate developers and security teams about the risks of using cryptographic libraries with insufficient data authenticity verification.
Monitor threat intelligence sources for any emerging exploits targeting this vulnerability.
For critical systems, consider additional cryptographic safeguards such as hardware security modules (HSMs) to protect private keys from software-level attacks.

Description

CVE-2026-23966 is a critical vulnerability in the sm-crypto JavaScript library, which implements Chinese cryptographic algorithms SM2, SM3, and SM4. The flaw exists in the SM2 decryption logic prior to version 0.3.14, allowing an attacker to recover the private key by interacting with the decryption interface multiple times, typically within several hundred interactions. This vulnerability does not require authentication or user interaction and can be exploited remotely over the network. The impact includes full compromise of confidentiality and integrity of cryptographic operations relying on the affected private keys. The issue has been patched in version 0.3.14. European organizations using sm-crypto in their applications, especially those handling sensitive data or relying on SM2 for secure communications, are at risk.

Impact

For European organizations, the impact of this vulnerability can be severe if sm-crypto is used in applications that handle sensitive or regulated data, especially in sectors such as finance, telecommunications, or government services that may rely on Chinese cryptographic standards for compliance or interoperability. The private key recovery allows attackers to decrypt confidential communications, manipulate data integrity, and potentially conduct identity theft or fraud. This can lead to data breaches, regulatory penalties under GDPR, loss of customer trust, and disruption of secure communications. The vulnerability's remote exploitability without authentication increases the risk of widespread attacks. Organizations using sm-crypto in client-side or server-side JavaScript environments are particularly vulnerable. Additionally, supply chain risks exist if third-party software or services incorporate vulnerable versions of sm-crypto. The lack of known exploits in the wild currently provides a window for mitigation, but the critical nature demands prompt action.

Summary

The vulnerability identified as CVE-2026-23966 affects the sm-crypto JavaScript library developed by JuneAndGreen, which provides implementations of Chinese cryptographic algorithms SM2 (asymmetric encryption), SM3 (hashing), and SM4 (symmetric encryption). Specifically, the flaw lies in the SM2 decryption logic in versions prior to 0.3.14. SM2 is widely used in Chinese cryptographic standards for public key encryption and digital signatures. The vulnerability is categorized under CWE-345, indicating insufficient verification of data authenticity. An attacker can exploit this by repeatedly interacting with the SM2 decryption interface, performing several hundred decryption operations to recover the private key fully. This private key recovery enables the attacker to decrypt confidential data, forge signatures, and impersonate legitimate users or services. The vulnerability is remotely exploitable without requiring privileges or user interaction, making it highly dangerous. The CVSS v3.1 score of 9.1 reflects its critical severity, with high impact on confidentiality and integrity but no impact on availability. Although no known exploits are reported in the wild yet, the ease of exploitation and severity warrant immediate attention. The patch was released in version 0.3.14, which corrects the decryption logic to prevent private key leakage.

CWE-345Insufficient Verification of Data Authenticity (opens in a new tab)
Class weaknessOWASP Top 10 A08:2025: Software or Data Integrity Failures (opens in a new tab)
The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
OWASP Cheat Sheets
XML Security (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
REST Assessment (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.2 (opens in a new tab)
V3.5.3 (opens in a new tab)
V13.2.6 (opens in a new tab)
Attack patterns
JSON Hijacking (aka JavaScript Hijacking) (opens in a new tab)
Cache Poisoning (opens in a new tab)
DNS Cache Poisoning (opens in a new tab)
Spoofing of UDDI/ebXML Messages (opens in a new tab)
Application API Message Manipulation via Man-in-the-Middle (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Jan 2026, 08:50 UTC

WeaknessesCWE-345

Technical details

References

Community reviews

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