CRITICAL CVSS 9.1
Published: 2026-01-22

CVE-2026-23966

juneandgreen sm-crypto Security Advisory (CVE-2026-23966)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-23966 impacting juneandgreen sm-crypto. Evaluated with CVSS Base Score of 9.1 (CRITICAL).

Original NVD Description

Source: NIST NVD
sm-crypto provides JavaScript implementations of the Chinese cryptographic algorithms SM2, SM3, and SM4. A private key recovery vulnerability exists in the SM2 decryption logic of sm-crypto prior to version 0.3.14. By interacting with the SM2 decryption interface multiple times, an attacker can fully recover the private key within approximately several hundred interactions. Version 0.3.14 patches the issue.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
None (PR:N)
Unauthenticated execution
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
High (C:H)
Total information disclosure
Integrity
High (I:H)
Total modification of target system
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product juneandgreen / sm-crypto
Affected Versions *
Weakness Enumeration CWE-345

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2026-23966 impacting juneandgreen sm-crypto.

⚡ Nuclei Detection Template (YAML) cve-2026-23966.yaml
id: cve-2026-23966

info:
  name: juneandgreen sm-crypto - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-23966 affecting juneandgreen sm-crypto.
    Evaluation: sm-crypto provides JavaScript implementations of the Chinese cryptographic algorithms SM2, SM3, and SM4. A private key recovery vulnerability exists i...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-23966
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
    cvss-score: 9.1
    cve-id: CVE-2026-23966
    cwe-id: CWE-345
  tags: cve,cve-2026-23966,juneandgreen,sm-crypto,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "sm-crypto"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-23966.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-23966
# Target: juneandgreen sm-crypto | CVSS: 9.1 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-23966 (juneandgreen sm-crypto)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against juneandgreen sm-crypto scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2026-23966.sh
# Recommended Remediation & Patching Commands for CVE-2026-23966
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install sm-crypto 2>/dev/null || \
sudo dnf upgrade sm-crypto 2>/dev/null || \
sudo yum update sm-crypto

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i sm-crypto 2>/dev/null || rpm -qa | grep -i sm-crypto

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

🔗 Verified Technical References

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-23966 in juneandgreen sm-crypto?

Review vendor-specific security notices and update juneandgreen sm-crypto packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2026-23966?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2026-23966?

CVE-2026-23966 is classified with a CVSS 3.1 Base Score of 9.1 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.1
CRITICAL SEVERITY
CVE ID CVE-2026-23966
Weakness CWE-345
Vendor juneandgreen
Product sm-crypto
Published 2026-01-22
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N