CVE-2026-6596Public exploitNetwork attack vector

Unauthenticated file upload via unchecked deprecated endpoint

Published Apr 20, 2026 · Updated Apr 20, 2026

Missing access control in Langflow OSS 1.0 and 1.1.0 allows remote attackers to upload files through a deprecated API endpoint. The create_upload_file route in endpoints.py passes an attacker-supplied body and flow UUID to save_uploaded_file without authentication or a size limit. Any network caller that can reach the service can consume server disk space, write into a guessed flow cache, and receive the stored file's absolute path.

CVSS severity7.3
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing access control in Langflow OSS 1.0 and 1.1.0 allows remote attackers to upload files through a deprecated API endpoint. The create_upload_file route in endpoints.py passes an attacker-supplied body and flow UUID to save_uploaded_file without authentication or a size limit. Any network caller that can reach the service can consume server disk space, write into a guessed flow cache, and receive the stored file's absolute path.

The record

CVE
CVE-2026-6596
Published
Apr 20, 2026
Updated
Apr 20, 2026
Vendor
OpenBMC Project
Product
Langflow OSS
Classifications
CWE-284, CWE-434, T1190, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 20, 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=1.0
  2. Affected versionversion=1.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenBMC Project · Langflow OSSversion=1.0; version=1.1.0

Published CVSS scores

7.3VulDBCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
5.5VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
7.5VulDBAV:N/AC:L/Au:N/C:P/I:P/A:P

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-284Improper Access Control
CWE-434Unrestricted Upload of File with Dangerous Type
T1190Exploit Public-Facing Application
T1499.004Application or System Exploitation

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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