CVE-2026-55255 · Moderate · CISA KEV

Langflow Auth Bypass: Authenticated Attackers Can Execute Other Users' Flows

Threat Engine Auto-Feed · data current as of 2026-07-07

CVE-2026-55255 is an authorization bypass in Langflow, allowing an authenticated attacker to execute any flow belonging to another user. This vulnerability is actively exploited in the wild, as indicated by its inclusion in CISA's KEV catalog. While the EPSS is low, the confirmed exploitation warrants immediate attention.

  • CVSS:
  • EPSS percentile: 0.14148
  • Exploitation pressure: 33/100 (Moderate)

Exploitation reality: listed in CISA KEV (exploited in the wild) · EPSS 14th percentile. Threat × Vulnerability from public signals — impact depends on your environment.

Weakness —

This vulnerability is an authorization bypass, meaning that a system designed to restrict access to certain functions or data based on user permissions fails to do so properly. In this case, an authenticated user can bypass these checks by manipulating a user-controlled key (specifically, a victim's flow ID) to access and execute resources that should be restricted to other users.

Who's at risk

Exposure: unknown · Auth: unknown · unknown

Enterprise profiles most at risk

  • Organizations using Langflow in multi-user environments
  • Financial services organizations (due to assessed targeting by FIN7, LockBit affiliates, APT38)
  • Technology organizations (due to assessed targeting by APT29, Scattered Spider)

Misconfigurations that escalate it

  • Any Langflow deployment where multiple users share the same instance
  • Inadequate monitoring of user activity and access patterns within Langflow

High-impact scenarios

  • Unauthorized execution of critical workflows belonging to other users, potentially leading to data manipulation or unauthorized actions.
  • Compromise of sensitive data or intellectual property processed by Langflow flows.
  • Lateral movement within an organization's systems if flows interact with other internal services.

Likely adversaries

  • FIN7 — Financial services (Assessed)
  • LockBit affiliates — Financial services (Assessed)
  • APT38 (Lazarus) — Financial services (Assessed)
  • APT29 (Cozy Bear) — Technology (Assessed)
  • Scattered Spider — Technology (Assessed)

What to do (defensive)

Detect

  • Monitor Langflow logs for unusual flow execution patterns or attempts to access flows by users who are not the owner.
  • Implement robust logging for all Langflow API requests, specifically looking for manipulation of flow IDs by authenticated users.

Contain

  • Isolate Langflow instances from critical internal networks if immediate patching is not feasible.
  • Review and restrict user permissions within Langflow to the absolute minimum required.

Patch

  • Apply vendor-provided patches for Langflow (CVE-2026-55255) as soon as they become available.

Frontier verdict — Moderate

High priority due to active exploitation in the wild (CISA KEV) and potential for significant impact via unauthorized flow execution by authenticated attackers.

For detection-engineering and awareness only · point-in-time · not security advice · sourced from NVD, FIRST EPSS, CISA KEV. Adversary mappings are assessments unless cited.