Security Digest · Vulnerability record
CVE-2026-55450: Langflow: Unauthenticated file upload leads to DoS (space exhaustion) and information leak
Langflow is a tool for building and deploying AI-powered agents and workflows.
CVSS 9.3 Critical EPSS 1.2% · p68
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 1.2%, percentile 68: FIRST’s model estimates a 1.2% chance of exploitation activity in the next 30 days, higher than 68% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
langflow(PyPI) < 1.9.1, fixed in 1.9.1. Check your lockfile, including transitive dependencies.
What it is
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.
From the GitHub advisory
Summary 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 adition, 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.
Tested on commit 2d67402b1dbaefcbce85a244d4a6cd5e4bda1cfe
Details Code is in langflow/api/v1/endpoints.py:
Weakness type: CWE-200, CWE-306, CWE-400.
Product: langflow (PyPI) · Assigned by: GitHub_M · Published: 2026-06-23
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| PyPI | langflow | < 1.9.1 | 1.9.1 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| langflow-ai | langflow | < 1.9.1 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.3 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H |
| GitHub | 3.1 | 9.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 1.19% probability of exploitation activity in the next 30 days; percentile 68.
Timeline
- — GitHub-reviewed advisory GHSA-x223-p2gf-v735 published (critical)
- — CVE record last updated
- — CVE record published by GitHub_M
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-x223-p2gf-v735 github.com
- CVE.org record CVE-2026-55450 cve.org
- NVD entry CVE-2026-55450 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com