---
title: "CVE-2026-55255: Langflow Authorization Bypass Through User-Controlled Key Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-55255/
description: "CVE-2026-55255 (Langflow Langflow): Exploited in the wild (CISA KEV). Langflow is a tool for building and deploying AI-powered agents and workflows. Prior…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-06-23
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-55255"
kev: true
cvss: 8.4
epss: 0.00887
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-55255: Langflow Authorization Bypass Through User-Controlled Key Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Langflow Langflow. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-07-07, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-07-10 ; treat that as the outer limit, not the target.
- EPSS 0.9% , percentile 59: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 59% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Editorial verdict: Act now. Langflow CVE-2026-9198: Exploited Unauthenticated RCE — Langflow is now the most repeatedly exploited AI-agent builder on CISA's list; any network-reachable instance below 1.10.1 should be patched today and checked for compromise.

## What it is

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.

## Affected products (CVE record)

- langflow-ai langflow: < 1.9.1

## Severity

- GitHub_M CVSS 3.1: 8.4 `CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L`

## Exploitation

- CISA KEV: added 2026-07-07; federal due date 2026-07-10. Known ransomware use: Unknown.
- CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
- CISA SSVC assessment: exploitation active , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.89% probability of exploitation activity in the next 30 days; percentile 59.

## Sources

- [Listed in CISA KEV notes (github.com)](https://github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2)
- [CVE.org record CVE-2026-55255](https://www.cve.org/CVERecord?id=CVE-2026-55255)
- [NVD entry CVE-2026-55255](https://nvd.nist.gov/vuln/detail/CVE-2026-55255)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-55255)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk)
- [github.com](https://github.com/langflow-ai/langflow/pull/12832)
- [github.com](https://github.com/langflow-ai/langflow/commit/2c9f498d664a3c32698b57d7c5e752625291060e)
- [webflow.sysdig.com](https://webflow.sysdig.com/blog/understanding-langflow-cve-2026-55255-and-why-higher-cvss-vulnerabilities-arent-always-the-most-exploited)

---
Source page: https://erroneo.us/security/cve/CVE-2026-55255/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt