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

> Authenticated attackers can access and execute other users' AI workflows by manipulating flow IDs in API requests.

- **Severity:** High 8.4 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L`)
- **Exploited in the wild:** Yes, since 7 Jul 2026 (CISA KEV)
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Jun 2026
- **Updated:** 7 Oct 2026
- **Also known as:** GHSA-qrpv-q767-xqq2, PYSEC-2026-221, ROOT-APP-PYPI-CVE-2026-55255

## 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 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-55255?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `langflow` | PyPI | All versions | 1.9.1 |
| `langflow` | PyPI | All versions | 1.9.1 |
| `langflow` | PyPI | All versions | 1.9.2 |

Products: 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.

## 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:

- https://github.com/rootdirective-sec/CVE-2026-55255-Lab (github_poc): https://github.com/rootdirective-sec/CVE-2026-55255-Lab

## 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-2026-55255 and fix it if it is affected.

What it is: 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.
Exploitation: Yes. Attackers have exploited CVE-2026-55255 in the wild since at least 7 Jul 2026.

Affected packages and fixed versions:
- langflow (PyPI): affected all versions; fixed in 1.9.1
- langflow (PyPI): affected all versions; fixed in 1.9.1
- langflow (PyPI): affected all versions; fixed in 1.9.2

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-2026-55255/ (Markdown: https://insights.sbomify.com/CVE-2026-55255/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55255
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55255
- OSV: https://osv.dev/vulnerability/CVE-2026-55255

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55255/
Summaries are generated and may contain mistakes; the official description above is the record.