CVE-2026-7663 Unauthenticated Cross-User MCP Resource Access and Tool Execution via Streamable Transport Authorization Bypass

What is CVE-2026-7663?

CVE-2026-7663 is a critical missing authorization vulnerability in Langflow Langflow, published on 30 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

IBM Langflow OSS 1.0.0 through 1.9.6 could allow unauthenticated attackers to access protected MCP project resources and execute MCP operations due to improper authorization enforcement in the Streamable MCP transport endpoint.

Weakness: CWE-863, CWE-285

Which versions are affected by CVE-2026-7663?

It affects 1 product.

Products include Langflow Langflow.

How do I fix CVE-2026-7663?

No fix has been published for CVE-2026-7663 yet. Limit exposure of the affected software until one is available.

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

Is CVE-2026-7663 being exploited?

There is no known exploitation of CVE-2026-7663 in the wild and no public exploit code.

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-5wjx-cxqm-p8r4.