MEDIUM CVSS 4.8
Published: 2026-02-24

CVE-2026-26351

getsimple-ce getsimple_cms Security Advisory (CVE-2026-26351)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-26351 impacting getsimple-ce getsimple_cms. Evaluated with CVSS Base Score of 4.8 (MEDIUM).

Original NVD Description

Source: NIST NVD
GetSimpleCMS Community Edition (CE) versions prior to 3.3.22 (3.3.16 tested) contains a stored cross-site scripting (XSS) vulnerability in the Theme to Components functionality within components.php. User-supplied input provided to the "slug" field of a component is stored without proper output encoding. While other fields are sanitized using safe_slash_html(), the slug parameter is written to XML and later rendered in the administrative interface without sanitation, resulting in persistent execution of arbitrary JavaScript. An authenticated administrator can inject malicious script content that executes whenever the affected Components page is viewed by any authenticated user, enabling session hijacking, unauthorized administrative actions, and persistent compromise of the CMS administrative interface.

📊 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
Required (UI:R)
User must click or open resource
Scope
Changed (S:C)
Impacts components beyond caller authority
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 getsimple-ce / getsimple_cms
Affected Versions *
Weakness Enumeration CWE-79

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-2026-26351 impacting getsimple-ce getsimple_cms.

⚡ Nuclei Detection Template (YAML) cve-2026-26351.yaml
id: cve-2026-26351

info:
  name: getsimple-ce getsimple_cms - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-26351 affecting getsimple-ce getsimple_cms.
    Evaluation: GetSimpleCMS Community Edition (CE) versions prior to 3.3.22 (3.3.16 tested) contains a stored cross-site scripting (XSS) vulnerability in the Theme t...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-26351
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
    cvss-score: 4.8
    cve-id: CVE-2026-26351
    cwe-id: CWE-79
  tags: cve,cve-2026-26351,getsimple-ce,getsimple_cms,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "getsimple_cms"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-26351.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-26351
# Target: getsimple-ce getsimple_cms | CVSS: 4.8 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-26351 (getsimple-ce getsimple_cms)...")
    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 getsimple-ce getsimple_cms 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-2026-26351.sh
# Recommended Remediation & Patching Commands for CVE-2026-26351
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install getsimple_cms 2>/dev/null || \
sudo dnf upgrade getsimple_cms 2>/dev/null || \
sudo yum update getsimple_cms

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

# 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-2026-26351 in getsimple-ce getsimple_cms?

Review vendor-specific security notices and update getsimple-ce getsimple_cms 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-2026-26351?

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-2026-26351?

CVE-2026-26351 is classified with a CVSS 3.1 Base Score of 4.8 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
4.8
MEDIUM SEVERITY
CVE ID CVE-2026-26351
Weakness CWE-79
Vendor getsimple-ce
Product getsimple_cms
Published 2026-02-24
Vector CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N