CVE-2026-33309Public exploitNetwork attack vector

Authenticated RCE via multipart filename path traversal

Published Mar 24, 2026 · Updated Mar 24, 2026

Path traversal in Langflow OSS 1.2.0 through 1.8.1 allows remote authenticated users to write arbitrary host files through v2 uploads. The POST /api/v2/files/ multipart handler passes its upload filename verbatim, and LocalStorageService joins it without enforcing storage-boundary containment. Valid Langflow credentials and network access to the API are required; overwriting Python components or authorized_keys enables host code execution.

CVSS severity9.9
Critical
EPSS probability11.06%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Langflow OSS 1.2.0 through 1.8.1 allows remote authenticated users to write arbitrary host files through v2 uploads. The POST /api/v2/files/ multipart handler passes its upload filename verbatim, and LocalStorageService joins it without enforcing storage-boundary containment. Valid Langflow credentials and network access to the API are required; overwriting Python components or authorized_keys enables host code execution.

The record

CVE
CVE-2026-33309
Published
Mar 24, 2026
Updated
Mar 24, 2026
Vendor
OpenBMC Project
Product
Langflow OSS
Classifications
CWE-22, CWE-284, CWE-94, CWE-73, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 1.2.0, < 1.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OpenBMC Project · Langflow OSSversion=>= 1.2.0, < 1.9.0

Published CVSS scores

9.9GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-284Improper Access Control
CWE-94Improper Control of Generation of Code ('Code Injection')
CWE-73External Control of File Name or Path
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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