HIGH CVSS 8.8
Published: 2026-03-11

CVE-2026-20046

cisco ios_xr Security Advisory (CVE-2026-20046)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-20046 impacting cisco ios_xr. Evaluated with CVSS Base Score of 8.8 (HIGH).

Original NVD Description

Source: NIST NVD
A vulnerability in task group assignment for a specific CLI command in Cisco IOS XR Software could allow an authenticated, local attacker to elevate privileges and gain full administrative control of an affected device. This vulnerability is due to incorrect mapping of a command to task groups within the source code. An attacker with a low-privileged account could exploit this vulnerability by using the CLI command to bypass the task group–based checks. A successful exploit could allow the attacker to elevate privileges and perform actions on an affected device without authorization checks.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Local (AV:L)
Requires local system execution permissions
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
Changed (S:C)
Impacts components beyond caller authority
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 cisco / ios_xr
Affected Versions *
Weakness Enumeration CWE-264

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-2026-20046 impacting cisco ios_xr.

⚡ Nuclei Detection Template (YAML) cve-2026-20046.yaml
id: cve-2026-20046

info:
  name: cisco ios_xr - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-20046 affecting cisco ios_xr.
    Evaluation: A vulnerability in task group assignment for a specific CLI command in Cisco IOS XR Software could allow an authenticated, local attacker to elevate p...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-20046
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
    cvss-score: 8.8
    cve-id: CVE-2026-20046
    cwe-id: CWE-264
  tags: cve,cve-2026-20046,cisco,ios_xr,high

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "ios_xr"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-20046.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-20046
# Target: cisco ios_xr | CVSS: 8.8 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-20046 (cisco ios_xr)...")
    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 ios_xr 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-2026-20046.sh
# Recommended Remediation & Patching Commands for CVE-2026-20046
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install ios_xr 2>/dev/null || \
sudo dnf upgrade ios_xr 2>/dev/null || \
sudo yum update ios_xr

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

# 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

Authorities
  • No records filed in this category.
Distributions
  • No records filed in this category.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-20046 in cisco ios_xr?

Review vendor-specific security notices and update cisco ios_xr 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-2026-20046?

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-2026-20046?

CVE-2026-20046 is classified with a CVSS 3.1 Base Score of 8.8 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.8
HIGH SEVERITY
CVE ID CVE-2026-20046
Weakness CWE-264
Vendor cisco
Product ios_xr
Published 2026-03-11
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H