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

> Unauthenticated attackers can bypass authorization in IBM Langflow OSS to access protected resources and execute MCP operations.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 30 Jun 2026
- **Updated:** 1 Jul 2026
- **Also known as:** GHSA-5wjx-cxqm-p8r4

## 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 (Incorrect Authorization), CWE-285 (Improper Authorization)

## Which versions are affected by CVE-2026-7663?

It affects 1 product.


Products: 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.

## 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](https://insights.sbomify.com/CVE-2026-9198/): IBM Langflow Code Injection (critical 9.8, exploited in the wild)
- [CVE-2026-0770](https://insights.sbomify.com/CVE-2026-0770/): Langflow Inclusion of Functionality from Untrusted Control Sphere (critical 9.8, exploited in the wild)
- [CVE-2025-3248](https://insights.sbomify.com/CVE-2025-3248/): Langflow Missing Authentication (critical 9.8, exploited in the wild)
- [CVE-2025-34291](https://insights.sbomify.com/CVE-2025-34291/): Langflow Origin Validation Error (critical 9.4, exploited in the wild)
- [CVE-2026-33017](https://insights.sbomify.com/CVE-2026-33017/): Langflow Code Injection (critical 9.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-7663 and fix it if it is affected.

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

Affected product: Langflow Langflow. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-7663/ (Markdown: https://insights.sbomify.com/CVE-2026-7663/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-7663
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-7663
- OSV: https://osv.dev/vulnerability/CVE-2026-7663

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-7663/
Summaries are generated and may contain mistakes; the official description above is the record.