MEDIUM CVSS 5.3
Published: 2026-03-10

CVE-2026-31821

sylius sylius Security Advisory (CVE-2026-31821)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-31821 impacting sylius sylius. Evaluated with CVSS Base Score of 5.3 (MEDIUM).

Original NVD Description

Source: NIST NVD
Sylius is an Open Source eCommerce Framework on Symfony. The POST /api/v2/shop/orders/{tokenValue}/items endpoint does not verify cart ownership. An unauthenticated attacker can add items to other registered customers' carts by knowing the cart tokenValue. An attacker who obtains a cart tokenValue can add arbitrary items to another customer's cart. The endpoint returns the full cart representation in the response (HTTP 201). The issue is fixed in versions: 2.0.16, 2.1.12, 2.2.3 and above.

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

🎯 Affected Versions Matrix

Affected Product sylius / sylius
Affected Versions *
Weakness Enumeration CWE-862

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-2026-31821 impacting sylius sylius.

⚡ Nuclei Detection Template (YAML) cve-2026-31821.yaml
id: cve-2026-31821

info:
  name: sylius sylius - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-31821 affecting sylius sylius.
    Evaluation: Sylius is an Open Source eCommerce Framework on Symfony. The POST /api/v2/shop/orders/tokenValue/items endpoint does not verify cart ownership. An u...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-31821
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
    cvss-score: 5.3
    cve-id: CVE-2026-31821
    cwe-id: CWE-862
  tags: cve,cve-2026-31821,sylius,sylius,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "sylius"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-31821.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-31821
# Target: sylius sylius | CVSS: 5.3 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-31821 (sylius sylius)...")
    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 sylius sylius 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-2026-31821.sh
# Recommended Remediation & Patching Commands for CVE-2026-31821
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install sylius 2>/dev/null || \
sudo dnf upgrade sylius 2>/dev/null || \
sudo yum update sylius

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

# 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-2026-31821 in sylius sylius?

Review vendor-specific security notices and update sylius sylius 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-2026-31821?

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-2026-31821?

CVE-2026-31821 is classified with a CVSS 3.1 Base Score of 5.3 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
5.3
MEDIUM SEVERITY
CVE ID CVE-2026-31821
Weakness CWE-862
Vendor sylius
Product sylius
Published 2026-03-10
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N