HIGH CVSS 7.2
Published: 2026-06-26

CVE-2026-9640

canonical lxd Security Advisory (CVE-2026-9640)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-9640 impacting canonical lxd. Evaluated with CVSS Base Score of 7.2 (HIGH).

Original NVD Description

Source: NIST NVD
A privilege escalation vulnerability exists in LXD from 6.0 before 6.9, 5.21.0 before 5.21.5, and 5.0.0 before 5.0.7 regarding the handling of project-restriction policies during snapshot restoration.. An authenticated project operator in a restricted multi-tenant environment can bypass policy restrictions by importing a maliciously crafted instance backup containing restricted configuration keys within a snapshot. When the snapshot is restored, these restricted keys are applied to the live instance without policy validation. Starting the modified instance grants the operator unauthorized host root access.

📊 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
High (PR:H)
Administrative credentials required
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
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product canonical / lxd
Affected Versions *
Weakness Enumeration CWE-863

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-2026-9640 impacting canonical lxd.

⚡ Nuclei Detection Template (YAML) cve-2026-9640.yaml
id: cve-2026-9640

info:
  name: canonical lxd - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-9640 affecting canonical lxd.
    Evaluation: A privilege escalation vulnerability exists in LXD from 6.0 before 6.9, 5.21.0 before 5.21.5, and 5.0.0 before 5.0.7 regarding the handling of project...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-9640
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 7.2
    cve-id: CVE-2026-9640
    cwe-id: CWE-863
  tags: cve,cve-2026-9640,canonical,lxd,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "lxd"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-9640.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-9640
# Target: canonical lxd | CVSS: 7.2 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-9640 (canonical lxd)...")
    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 canonical lxd 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-2026-9640.sh
# Recommended Remediation & Patching Commands for CVE-2026-9640
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install lxd 2>/dev/null || \
sudo dnf upgrade lxd 2>/dev/null || \
sudo yum update lxd

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

# 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.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-9640 in canonical lxd?

Review vendor-specific security notices and update canonical lxd 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-2026-9640?

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-2026-9640?

CVE-2026-9640 is classified with a CVSS 3.1 Base Score of 7.2 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
7.2
HIGH SEVERITY
CVE ID CVE-2026-9640
Weakness CWE-863
Vendor canonical
Product lxd
Published 2026-06-26
Vector CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H