MEDIUM CVSS 6.7
Published: 2026-04-09

CVE-2026-33791

juniper junos Security Advisory (CVE-2026-33791)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-33791 impacting juniper junos. Evaluated with CVSS Base Score of 6.7 (MEDIUM).

Original NVD Description

Source: NIST NVD
An OS Command Injection vulnerability in the CLI processing of Juniper Networks Junos OS and Junos OS Evolved allows a local, high-privileged attacker executing specific, crafted CLI commands to inject arbitrary shell commands as root, leading to a complete compromise of the system. Certain 'set system' commands, when executed with crafted arguments, are not properly sanitized, allowing for arbitrary shell injection. These shell commands are executed as root, potentially allowing for complete control of the vulnerable system. This issue affects: Junos OS:  * all versions before 22.4R3-S8,  * from 23.2 before 23.2R2-S5,  * from 23.4 before 23.4R2-S7,  * from 24.2 before 24.2R2-S2,  * from 24.4 before 24.4R2,  * from 25.2 before 25.2R2;  Junos OS Evolved:  * all versions before 22.4R3-S8-EVO,  * from 23.2 before 23.2R2-S5-EVO,  * from 23.4 before 23.4R2-S7-EVO,  * from 24.2 before 24.2R2-S2-EVO,  * from 24.4 before 24.4R2-EVO,  * from 25.2 before 25.2R1-S1-EVO, 25.2R2-EVO.

📊 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
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 juniper / junos
Affected Versions *
Weakness Enumeration CWE-78

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-2026-33791 impacting juniper junos.

⚡ Nuclei Detection Template (YAML) cve-2026-33791.yaml
id: cve-2026-33791

info:
  name: juniper junos - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-33791 affecting juniper junos.
    Evaluation: An OS Command Injection vulnerability in the CLI processing of Juniper Networks Junos OS and Junos OS Evolved allows a local, high-privileged attacker...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-33791
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 6.7
    cve-id: CVE-2026-33791
    cwe-id: CWE-78
  tags: cve,cve-2026-33791,juniper,junos,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "junos"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-33791.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-33791
# Target: juniper junos | CVSS: 6.7 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-33791 (juniper junos)...")
    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 juniper junos 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-2026-33791.sh
# Recommended Remediation & Patching Commands for CVE-2026-33791
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install junos 2>/dev/null || \
sudo dnf upgrade junos 2>/dev/null || \
sudo yum update junos

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

# 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-2026-33791 in juniper junos?

Review vendor-specific security notices and update juniper junos 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-2026-33791?

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-2026-33791?

CVE-2026-33791 is classified with a CVSS 3.1 Base Score of 6.7 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
6.7
MEDIUM SEVERITY
CVE ID CVE-2026-33791
Weakness CWE-78
Vendor juniper
Product junos
Published 2026-04-09
Vector CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H