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Fencer Intel
critical 9.3

CVE-2026-55450 json

Langflow: Unauthenticated file upload leads to DoS (space exhaustion) and information leak

published 4mo ago modified 17d ago also GHSA-x223-p2gf-v735 , PYSEC-2026-224 , EUVD-2026-38511

cvss
9.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi langflow 1.9.1
  • langflow langflow 1.9.1

Is CVE-2026-55450 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
4mo ago

Exploit prediction

1.19% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/langflow-ai/langflow/security/advisories/GHSA-x223-p2gf-v735 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 9.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H
OSV 3.1 9.3 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

Affected packages

ecosystem package affected fixed in
pypi langflow
<1.9.1
1.9.1

Affected products

  • langflow-ai langflow

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
  • CWE-306 Missing Authentication for Critical Functionality
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.