MEDIUM CVSS 6.4
Published: 2026-06-01

CVE-2026-45285

nextcloud nextcloud_server Security Advisory (CVE-2026-45285)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-45285 impacting nextcloud nextcloud_server. Evaluated with CVSS Base Score of 6.4 (MEDIUM).

Original NVD Description

Source: NIST NVD
Nextcloud is an open source content collaboration platform. From versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, when a user shares a folder or file with a Nextcloud Team that includes an external member (a person added via email address who does not have a Nextcloud account), the system automatically creates a public link for that external member. This public link is not displayed in the share section of the folder, so the folder owner has no knowledge of its existence. It is sent via email to the external member. It grants the same permissions (read, write, delete, reshare, download) as the Team’s access. An attacker who receives or intercepts this link can access, modify, delete, reshare, and download all data in the shared folder without any further authentication. The folder owner cannot see or revoke the link through the normal sharing interface. This issue has been patched in versions 32.0.9 and 33.0.3.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
High (AC:H)
Depends on race conditions or environment
Privileges Required
Low (PR:L)
Standard user access required
User Interaction
Required (UI:R)
User must click or open resource
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 nextcloud / nextcloud_server
Affected Versions *
Weakness Enumeration CWE-862

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-2026-45285 impacting nextcloud nextcloud_server.

⚡ Nuclei Detection Template (YAML) cve-2026-45285.yaml
id: cve-2026-45285

info:
  name: nextcloud nextcloud_server - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-45285 affecting nextcloud nextcloud_server.
    Evaluation: Nextcloud is an open source content collaboration platform. From versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, when a user shares a f...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-45285
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N
    cvss-score: 6.4
    cve-id: CVE-2026-45285
    cwe-id: CWE-862
  tags: cve,cve-2026-45285,nextcloud,nextcloud_server,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "nextcloud_server"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-45285.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-45285
# Target: nextcloud nextcloud_server | CVSS: 6.4 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-45285 (nextcloud nextcloud_server)...")
    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 nextcloud nextcloud_server 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-2026-45285.sh
# Recommended Remediation & Patching Commands for CVE-2026-45285
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install nextcloud_server 2>/dev/null || \
sudo dnf upgrade nextcloud_server 2>/dev/null || \
sudo yum update nextcloud_server

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

# 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-2026-45285 in nextcloud nextcloud_server?

Review vendor-specific security notices and update nextcloud nextcloud_server 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-2026-45285?

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-2026-45285?

CVE-2026-45285 is classified with a CVSS 3.1 Base Score of 6.4 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
6.4
MEDIUM SEVERITY
CVE ID CVE-2026-45285
Weakness CWE-862
Vendor nextcloud
Product nextcloud_server
Published 2026-06-01
Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N