{"items":[{"id":"NVI-00018538","kind":"vulnerability","title":"Langflow: Unauthenticated DoS through multipart form boundary file upload","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-qwqc-p3q8-wcg9","CVE-2026-55446"],"plain_summary":"GitHub lists this reviewed advisory for langflow. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-389ea399b5a4d8fffa6d057f701c6ef2"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-06-19T21:17:38.000Z","value":"7.5 high","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-389ea399b5a4d8fffa6d057f701c6ef2"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-389ea399b5a4d8fffa6d057f701c6ef2","url":"https://github.com/advisories/GHSA-qwqc-p3q8-wcg9","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-qwqc-p3q8-wcg9","publisher":"GitHub Advisory Database","observed_at":"2026-11-06T07:18:46.322Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-389ea399b5a4d8fffa6d057f701c6ef2"],"technology":"langflow","known_exclusions":[],"conditions_summary":"### Summary\nAn 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. \n\n### Details\nhttps://github.com/langflow-ai/langflow/blob/v1.0.18/src/backend/base/langflow/api/v1/files.py#L40\n\nThe 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. \n\nAdditionally, an attacker doesn't even need to know a valid UUID of a flow to send this request because the server will still try to process the large boundary even with any random value in place of the flow ID. \n\n### PoC\n\nAn attacker makes this request to upload a file without valid authentication information or a valid flow ID: \n\n```\nPOST /api/v1/files/upload/test HTTP/1.1\nHost: 127.0.0.1:7860\nContent-Length: 3000192\nAccept-Language: en-US,en;q=0.9\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64","public_affected_ranges":["< 1.0.19"]}],"null_published_at":"2026-11-07T07:07:39.850Z","source_updated_at":"2026-06-19T21:17:38.000Z","source_disclosed_at":"2026-06-19T21:17:37.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-06T07:18:46.322Z"}],"next_cursor":null,"snapshot_revision":"42594"}