TI-2026-40012 Aliases CVE-2026-55446 GHSA-qwqc-p3q8-wcg9

Langflow: Unauthenticated DoS through multipart form boundary file upload

HIGH 72CWE-400Published 2026-06-23 · Updated 2026-06-23

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-400.

Summary

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.0.19, an attacker can send a /api/v1/files/upload/ request without any authentication token/cookies and abuse a very long multipart form boundary to make the langflow app unusable for all users for an indefinite amount of time. This vulnerability is fixed in 1.0.19.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00581 48th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed langflow (langflow-ai): 1.0.19langflow (PyPI): 1.0.19

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Langflow	langflow	before 1.0.19	1.0.19	Patch available	CNA
—	langflow (PyPI)	before 1.0.19	1.0.19	Patch available	GHSA-qwqc-p3q8-wcg9

langflow VendorLangflow Affected before 1.0.19 Fixed in 1.0.19 Patch available CNA
langflow (PyPI) Vendor— Affected before 1.0.19 Fixed in 1.0.19 Patch available GHSA-qwqc-p3q8-wcg9

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:langflow:langflow::::::::	before 1.0.19	Vulnerable	Langflow

cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:* Versions before 1.0.19 Vulnerable ·Langflow

Remediation

Fix · CNA langflow (langflow-ai) Fixed in 1.0.19
Fix · GHSA-qwqc-p3q8-wcg9 langflow (PyPI) Fixed in 1.0.19 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-55446
2026-10-03 Alias added: GHSA-qwqc-p3q8-wcg9

References

Exploit 1

https://github.com/langflow-ai/langflow/security/advisories/GHSA-qwqc-p3q8-wcg9

Patch 1

https://github.com/langflow-ai/langflow/pull/3923

Other 2

TI-2026-08085 Unauthenticated Remote Code Execution via Auto-Login Bypass and Code Validation KEVCVSS 3.1CRITICAL 9.8
TI-2026-00553 Langflow exec_globals Inclusion of Functionality from Untrusted Control Sphere Remote… KEVCVSS 3.0CRITICAL 9.8
TI-2025-24427 Langflow <= 1.6.9 CORS Misconfiguration to Token Hijack & RCE KEVCVSS 4.0CRITICAL 9.4
TI-2025-02845 Langflow < 1.3.0 Unauthenticated RCE via /api/v1/validate/code KEVCVSS 3.1CRITICAL 9.8
TI-2026-25463 Langflow has Unauthenticated Remote Code Execution via Public Flow Build Endpoint KEVCVSS 4.0CRITICAL 9.3
TI-2026-39928 Authorization bypass in langflow KEVCVSS 3.1HIGH 8.4

See all 216 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences