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

Patch now

HIGH 8.4EXPLOITEDUPGRADE

CVE-2026-55255 is a high-severity flaw (CVSS 8.4) affecting langflow, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Exploited in the wild (CISA KEV)
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	8.4 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.9% (top 41%)
CISA exploited list	Yes, fix due 2026-07-10
Weakness	CWE-639
Published	2026-06-23
Last modified	2026-10-25

Publisher (CNA): GitHub, Inc. · Vendor: langflow

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-23 17:17 UTCPublished CVE record published
2026-07-07Exploited Added to the CISA Known Exploited Vulnerabilities list
2026-07-10Deadline CISA due date for US federal agencies to patch
2026-10-25 23:10 UTCUpdated Record last modified

langflow langflow UPGRADE

Affected: < 1.9.1

Fixed in: 1.9.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy langflow || rpm -q langflow || langflow --version

2. UPGRADE to 1.9.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade langflow

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade langflow

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Python (pip) · langflow · FIXED · 1.9.1 · vulnerable: < 1.9.1 · source

pip install --upgrade "langflow>=1.9.1" pip show langflow

Fedora 46 · mingw-qt5-qtwebkit · FIXED · 5.212.0-0.46.alpha4.fc46 · FEDORA-2026-46ae541c22 · source

sudo dnf upgrade --advisory=FEDORA-2026-46ae541c22

Fedora ELN · kdominate · FIXED · 26.08.2-2.eln159 · FEDORA-2026-b1d98239fd · source

sudo dnf upgrade --advisory=FEDORA-2026-b1d98239fd

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: rootdirective-sec/CVE-2026-55255-Lab (0 stars)
Write-up: webflow.sysdig.com/blog/understanding-langflow-cve-2026-55255-and-why-higher-cvss-vulnerab

Advisories and coverage

Research and news

Sysdig Threat Research: Understanding Langflow CVE-2026-55255, and why higher CVSS vulnerabilities aren't always the most exploited 2026-06-26

Verify at the official source NVD · CVE Program · CISA KEV catalog · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-55255?

langflow: upgrade to 1.9.1. Exact commands for each OS are on this page.

Is CVE-2026-55255 being exploited?

Yes. CVE-2026-55255 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

What does CVE-2026-55255 affect?

CVE-2026-55255 affects langflow. Severity is high (CVSS 8.4). 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 belon

How urgent is CVE-2026-55255?

Priority 74/100. High severity; Exploited in the wild (CISA KEV); Public exploit reference

Related CVEs

CVE-2026-7528 HIGH 7.1 UPGRADE IBM Langflow OSS 1.0.0 through 1.9.0 could allow a denial of service due to uncontrolled resource consumption.
CVE-2026-5022 MEDIUM 5.3 MITIGATE The '/api/v1/files/images/{flow_id}/{file_name}' endpoint does not enforce any authentication or authorization
CVE-2026-55450 CRITICAL 9.3 UPGRADE Langflow is a tool for building and deploying AI-powered agents and workflows
CVE-2026-10561 CRITICAL 10.0 UPGRADE IBM Langflow OSS 1.0.0 through 1.9.3 has an vulnerability due to an improper isolation of Python execution com
CVE-2026-55447 CRITICAL 9.6 UPGRADE Langflow is a tool for building and deploying AI-powered agents and workflows

References

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