MEDIUM CVSS 5.4
Published: 2026-05-14

CVE-2026-20210

cisco catalyst_sd-wan_manager Security Advisory (CVE-2026-20210)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-20210 impacting cisco catalyst_sd-wan_manager. Evaluated with CVSS Base Score of 5.4 (MEDIUM).

Original NVD Description

Source: NIST NVD
A vulnerability in the web UI of Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, could allow an authenticated, remote attacker with read-only permissions to modify configurations and perform unauthorized actions on an affected system. This vulnerability exists because of a failure to redact sensitive information within device configurations and templates. An attacker could exploit this vulnerability by elevating their read-only permissions to those of a high-privileged user. A successful exploit could allow the attacker to access or modify configuration settings within Cisco Catalyst SD-WAN Manager as a high-privileged user.

📊 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
Low (PR:L)
Standard user access required
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
Low (C:L)
Partial information leakage
Integrity
Low (I:L)
Partial data modification possible
Availability
None (A:N)
No system availability impact

🎯 Affected Versions Matrix

Affected Product cisco / catalyst_sd-wan_manager
Affected Versions *
Weakness Enumeration CWE-779

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-2026-20210 impacting cisco catalyst_sd-wan_manager.

⚡ Nuclei Detection Template (YAML) cve-2026-20210.yaml
id: cve-2026-20210

info:
  name: cisco catalyst_sd-wan_manager - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-20210 affecting cisco catalyst_sd-wan_manager.
    Evaluation: A vulnerability in the web UI of Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, could allow an authenticated, remote attacker with read-only ...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-20210
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
    cvss-score: 5.4
    cve-id: CVE-2026-20210
    cwe-id: CWE-779
  tags: cve,cve-2026-20210,cisco,catalyst_sd-wan_manager,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "catalyst_sd-wan_manager"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-20210.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-20210
# Target: cisco catalyst_sd-wan_manager | CVSS: 5.4 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-20210 (cisco catalyst_sd-wan_manager)...")
    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 cisco catalyst_sd-wan_manager 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-2026-20210.sh
# Recommended Remediation & Patching Commands for CVE-2026-20210
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install catalyst_sd-wan_manager 2>/dev/null || \
sudo dnf upgrade catalyst_sd-wan_manager 2>/dev/null || \
sudo yum update catalyst_sd-wan_manager

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

# 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-2026-20210 in cisco catalyst_sd-wan_manager?

Review vendor-specific security notices and update cisco catalyst_sd-wan_manager 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-2026-20210?

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-2026-20210?

CVE-2026-20210 is classified with a CVSS 3.1 Base Score of 5.4 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
5.4
MEDIUM SEVERITY
CVE ID CVE-2026-20210
Weakness CWE-779
Vendor cisco
Product catalyst_sd-wan_manager
Published 2026-05-14
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N