HomeCVE Intelligence › CVE-2026-55446
CVSS 7.5 HIGH Vulnerability

CVE-2026-55446: Langflow: Unauthenticated DoS through multipart form boundary file upload

Summary 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 amoun…

7.5CVSS Score
HIGHSeverity
NOCISA KEV
VulnerabilityImpact Type

📋 Vulnerability Details

CVE IDCVE-2026-55446
Vendorpip
Affected Productlangflow
Vulnerability TypeVulnerability
CVSS Score7.5 (HIGH)
Actively Exploited❌ No known exploitation
Patch StatusSee Vendor Advisory →
Reported ByCYBERDUDEBIVASH SENTINEL APEX Intelligence (via github_advisories)

🔬 Technical Analysis

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Summary

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.

Details

https://github.com/langflow-ai/langflow/blob/v1.0.18/src/backend/base/langflow/api/v1/files.py#L40 The file upload function will try to process the multipart form data even if it is malformed and contains a payload such as an extremely large amount of hyphens after the boundary. It also does not do the authentication check before trying to process this data so an unauthenticated attacker can perform this as well as authenticated users. Additionally, an attacker doesn't even need to know a valid UUID of a flow to send this request because the serv

🎯 Known Indicators of Compromise

{"type":"url","value":"https://github.com/langflow-ai/langflow/blob/v1.0.18/src/backend/base/langflow/api/v1/files.py#L40","confidence_score":0.82,"first_seen":"2026-06-19","source_count":1}

📚 Advisory References

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