HIGH CVSS 8.4
Published: 2026-06-23

CVE-2026-55255

langflow langflow Security Advisory (CVE-2026-55255)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-55255 impacting langflow langflow. Evaluated with CVSS Base Score of 8.4 (HIGH).

Original NVD Description

Source: NIST NVD
Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Network (AV:N)
Exploitable remotely across internet boundaries
Attack Complexity
High (AC:H)
Depends on race conditions or environment
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
High (C:H)
Total information disclosure
Integrity
High (I:H)
Total modification of target system
Availability
Low (A:L)
Partial service performance degradation

🎯 Affected Versions Matrix

Affected Product langflow / langflow
Affected Versions *
Weakness Enumeration CWE-639

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-2026-55255 impacting langflow langflow.

⚡ Nuclei Detection Template (YAML) cve-2026-55255.yaml
id: cve-2026-55255

info:
  name: langflow langflow - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: high
  description: |
    Automated signature & scanner for CVE-2026-55255 affecting langflow langflow.
    Evaluation: Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerabilit...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-55255
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L
    cvss-score: 8.4
    cve-id: CVE-2026-55255
    cwe-id: CWE-639
  tags: cve,cve-2026-55255,langflow,langflow,high

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-2026-55255.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-55255
# Target: langflow langflow | CVSS: 8.4 (HIGH)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-55255 (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-2026-55255.sh
# Recommended Remediation & Patching Commands for CVE-2026-55255
# 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.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-55255 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-2026-55255?

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-2026-55255?

CVE-2026-55255 is classified with a CVSS 3.1 Base Score of 8.4 (HIGH). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
8.4
HIGH SEVERITY
CVE ID CVE-2026-55255
Weakness CWE-639
Vendor langflow
Product langflow
Published 2026-06-23
Vector CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L