CRITICAL CVSS 9.6
Published: 2026-05-12

CVE-2026-42048

langflow langflow Security Advisory (CVE-2026-42048)
↗ Official NIST NVD Record
Seeking technical exploit breakdowns or verified PoC code for CVE-2026-42048?
🔬 Search Writeups & Exploit Archive →

CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-42048 impacting langflow langflow. Evaluated with CVSS Base Score of 9.6 (CRITICAL).

Original NVD Description

Source: NIST NVD
Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.0, Langflow is vulnerable to Path Traversal in the Knowledge Bases API (DELETE /api/v1/knowledge_bases). This occurs because user-supplied knowledge base names are concatenated directly into file paths without proper sanitization or boundary validation. An authenticated attacker can exploit this flaw to delete arbitrary directories anywhere on the server's filesystem, leading to data loss and potential service disruption. This vulnerability is fixed in 1.9.0.

📊 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
Low (PR:L)
Standard user access required
User Interaction
None (UI:N)
Zero human interaction required
Scope
Changed (S:C)
Impacts components beyond caller authority
Confidentiality
None (C:N)
No data confidentiality impact
Integrity
High (I:H)
Total modification of target system
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product langflow / langflow
Affected Versions *
Weakness Enumeration CWE-22

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-2026-42048 impacting langflow langflow.

⚡ Nuclei Detection Template (YAML) cve-2026-42048.yaml
id: cve-2026-42048

info:
  name: langflow langflow - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: critical
  description: |
    Automated signature & scanner for CVE-2026-42048 affecting langflow langflow.
    Evaluation: Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.0, Langflow is vulnerable to Path Traversal in the Knowled...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-42048
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H
    cvss-score: 9.6
    cve-id: CVE-2026-42048
    cwe-id: CWE-22
  tags: cve,cve-2026-42048,langflow,langflow,critical

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "langflow"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-42048.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-42048
# Target: langflow langflow | CVSS: 9.6 (CRITICAL)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-42048 (langflow langflow)...")
    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 langflow langflow 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-2026-42048.sh
# Recommended Remediation & Patching Commands for CVE-2026-42048
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install langflow 2>/dev/null || \
sudo dnf upgrade langflow 2>/dev/null || \
sudo yum update langflow

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

# 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-2026-42048 in langflow langflow?

Review vendor-specific security notices and update langflow langflow 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-2026-42048?

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-2026-42048?

CVE-2026-42048 is classified with a CVSS 3.1 Base Score of 9.6 (CRITICAL). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
9.6
CRITICAL SEVERITY
CVE ID CVE-2026-42048
Weakness CWE-22
Vendor langflow
Product langflow
Published 2026-05-12
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H