CRITICAL CVSS 9.8
Published: 2026-02-25

CVE-2026-27641

jugmac00 flask-reuploaded Security Advisory (CVE-2026-27641)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-27641 impacting jugmac00 flask-reuploaded. Evaluated with CVSS Base Score of 9.8 (CRITICAL).

Original NVD Description

Source: NIST NVD
Flask-Reuploaded provides file uploads for Flask. A critical path traversal and extension bypass vulnerability in versions prior to 1.5.0 allows remote attackers to achieve arbitrary file write and remote code execution through Server-Side Template Injection (SSTI). Flask-Reuploaded has been patched in version 1.5.0. Some workarounds are available. Do not pass user input to the `name` parameter, use auto-generated filenames only, and implement strict input validation if `name` must be used.

📊 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
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 jugmac00 / flask-reuploaded
Affected Versions *
Weakness Enumeration CWE-1336

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-2026-27641 impacting jugmac00 flask-reuploaded.

⚡ Nuclei Detection Template (YAML) cve-2026-27641.yaml
id: cve-2026-27641

info:
  name: jugmac00 flask-reuploaded - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-27641 affecting jugmac00 flask-reuploaded.
    Evaluation: Flask-Reuploaded provides file uploads for Flask. A critical path traversal and extension bypass vulnerability in versions prior to 1.5.0 allows remot...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-27641
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2026-27641
    cwe-id: CWE-1336
  tags: cve,cve-2026-27641,jugmac00,flask-reuploaded,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "flask-reuploaded"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-27641.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-27641
# Target: jugmac00 flask-reuploaded | CVSS: 9.8 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-27641 (jugmac00 flask-reuploaded)...")
    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 jugmac00 flask-reuploaded 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-2026-27641.sh
# Recommended Remediation & Patching Commands for CVE-2026-27641
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install flask-reuploaded 2>/dev/null || \
sudo dnf upgrade flask-reuploaded 2>/dev/null || \
sudo yum update flask-reuploaded

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

# 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-2026-27641 in jugmac00 flask-reuploaded?

Review vendor-specific security notices and update jugmac00 flask-reuploaded 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-2026-27641?

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-2026-27641?

CVE-2026-27641 is classified with a CVSS 3.1 Base Score of 9.8 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.8
CRITICAL SEVERITY
CVE ID CVE-2026-27641
Weakness CWE-1336
Vendor jugmac00
Product flask-reuploaded
Published 2026-02-25
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H