CVE-2026-55450Public exploitNetwork attack vector

Unauthenticated disk exhaustion and path disclosure via upload

Published Jun 23, 2026 · Updated Jun 23, 2026

Missing authentication in Langflow before 1.9.1 allows remote attackers to exhaust server disk space and disclose an absolute cache path. The deprecated POST /api/v1/upload/{flow_id} route sends an arbitrary flow UUID and uploaded content to save_uploaded_file without authenticating the caller or enforcing max_file_size_upload, then returns file_path. Network access alone reaches the still-live route; repeated uploads consume storage, and each response reveals the server-side cache location.

CVSS severity9.3
Critical
EPSS probability1.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Missing authentication in Langflow before 1.9.1 allows remote attackers to exhaust server disk space and disclose an absolute cache path. The deprecated POST /api/v1/upload/{flow_id} route sends an arbitrary flow UUID and uploaded content to save_uploaded_file without authenticating the caller or enforcing max_file_size_upload, then returns file_path. Network access alone reaches the still-live route; repeated uploads consume storage, and each response reveals the server-side cache location.

The record

CVE
CVE-2026-55450
Published
Jun 23, 2026
Updated
Jun 23, 2026
Vendor
OpenBMC Project
Product
Langflow OSS
Classifications
CWE-400, CWE-200, CWE-306, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 1.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenBMC Project · Langflow OSSversion=< 1.9.1

Published CVSS scores

9.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo