{"items":[{"id":"NVI-00013993","kind":"vulnerability","title":"tornado: multipart split() creates huge temp list before max_parts check -> memory amplification DoS (httputil.py:34)","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-8423-8fgw-73vq"],"plain_summary":"GitHub lists this reviewed advisory for tornado. 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-2e30019601ffb1d4effae48b0676a067"],"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":[],"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-2e30019601ffb1d4effae48b0676a067","url":"https://github.com/advisories/GHSA-8423-8fgw-73vq","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-8423-8fgw-73vq","publisher":"GitHub Advisory Database","observed_at":"2026-11-02T02:21:50.763Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-2e30019601ffb1d4effae48b0676a067"],"technology":"tornado","known_exclusions":[],"conditions_summary":"## Description\n\n### Summary\n\n`parse_multipart_form_data` (httputil.py:34) calls\n`data.split(b\"--\"+boundary+b\"\\r\\n\")` **before** the `max_parts` check (:35).\nA 600KB body with 100k parts creates a 100k-element transient list first,\nthen rejects   transient memory amplification (each split element is a copy).\nPre-auth HTTP DoS.\n\n### Root cause\n\n```python\nparts = data[:final_boundary_index].split(b\"--\" + boundary + b\"\\r\\n\")  # :34  huge list first\nif len(parts) > config.max_parts:                                       # :35  check after\n    raise HTTPInputError(\"multipart/form-data has too many parts\")\n```\n\n### PoC\n\ngist: https://gist.github.com/afldl/649861f25d39b53b7edbe0298e171617\n`poc.py` + `output.txt` (100k parts from 600KB   transient list).\n\n### Fix\n\nCount separators without materializing the list (e.g. `data.count(b\"--\"+boundary)` first).\n\n### Credit\n\nReported by afldl, 2026-07.","public_affected_ranges":["<= 6.5.7"]}],"null_published_at":"2026-11-02T10:00:37.195Z","source_updated_at":"2026-09-01T20:17:39.000Z","source_disclosed_at":"2026-09-01T20:17:38.000Z","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":"2026-11-02T02:21:50.763Z"}],"next_cursor":null,"snapshot_revision":"42594"}