MEDIUM CVSS 6.1
Published: 2026-07-14

CVE-2026-45753

sensiolabs symfony Security Advisory (CVE-2026-45753)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-45753 impacting sensiolabs symfony. Evaluated with CVSS Base Score of 6.1 (MEDIUM).

Original NVD Description

Source: NIST NVD
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, UrlAttributeSanitizer::getSupportedAttributes() omits URL-valued attributes including action, formaction, poster, and cite, so configurations that admit those attributes can leave javascript: URIs unsanitized and enable XSS when the resulting HTML is rendered or a victim submits a form or clicks a button. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.

📊 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
None (PR:N)
Unauthenticated execution
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 sensiolabs / symfony
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-2026-45753 impacting sensiolabs symfony.

⚡ Nuclei Detection Template (YAML) cve-2026-45753.yaml
id: cve-2026-45753

info:
  name: sensiolabs symfony - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-45753 affecting sensiolabs symfony.
    Evaluation: Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, U...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-45753
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
    cvss-score: 6.1
    cve-id: CVE-2026-45753
    cwe-id: CWE-79
  tags: cve,cve-2026-45753,sensiolabs,symfony,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "symfony"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-45753.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-45753
# Target: sensiolabs symfony | CVSS: 6.1 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-45753 (sensiolabs symfony)...")
    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 sensiolabs symfony 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-2026-45753.sh
# Recommended Remediation & Patching Commands for CVE-2026-45753
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install symfony 2>/dev/null || \
sudo dnf upgrade symfony 2>/dev/null || \
sudo yum update symfony

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

# 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-2026-45753 in sensiolabs symfony?

Review vendor-specific security notices and update sensiolabs symfony 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-2026-45753?

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-2026-45753?

CVE-2026-45753 is classified with a CVSS 3.1 Base Score of 6.1 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
6.1
MEDIUM SEVERITY
CVE ID CVE-2026-45753
Weakness CWE-79
Vendor sensiolabs
Product symfony
Published 2026-07-14
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N