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

What is CVE-2026-55255?

CVE-2026-55255 is a high-severity missing authorization vulnerability in Langflow Langflow, published on 23 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

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.

Weakness: CWE-639

Which versions are affected by CVE-2026-55255?

3 open source packages ship an affected version, including langflow. It affects 1 product.

Products include Langflow Langflow.

How do I fix CVE-2026-55255?

Upgrade langflow to a fixed version for your release line: 1.9.1 or 1.9.2. US federal agencies must fix it by 10 Jul 2026.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-55255 being exploited?

Yes. Attackers have exploited CVE-2026-55255 in the wild since at least 7 Jul 2026.

Public exploit code: 1 proofs of concept on GitHub.

Other vulnerabilities in Langflow Langflow

• CVE-2026-9198 IBM Langflow Code Injection Exploited Critical 9.8
• CVE-2026-0770 Langflow Inclusion of Functionality from Untrusted Control Sphere Exploited Critical 9.8
• CVE-2025-3248 Langflow Missing Authentication Exploited Critical 9.8
• CVE-2025-34291 Langflow Origin Validation Error Exploited Critical 9.4
• CVE-2026-33017 Langflow Code Injection Exploited Critical 9.3

All Langflow Langflow vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-qrpv-q767-xqq2, PYSEC-2026-221, ROOT-APP-PYPI-CVE-2026-55255.