{"items":[{"id":"NVI-00009209","kind":"vulnerability","title":"Twisted: Unauthenticated Remote Denial of Service in the Twisted HTTP/2 Server via Rapid Stream Reset","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-vpp8-g58w-m8mp"],"plain_summary":"GitHub lists this reviewed advisory for Twisted. 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-f574ecea0fb88d339daab7037815e72a"],"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":"2026-10-29T16:41:06.000Z","value":"7.5 high","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-f574ecea0fb88d339daab7037815e72a"}],"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-f574ecea0fb88d339daab7037815e72a","url":"https://github.com/advisories/GHSA-vpp8-g58w-m8mp","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-vpp8-g58w-m8mp","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T21:55:49.621Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-f574ecea0fb88d339daab7037815e72a"],"technology":"Twisted","known_exclusions":[],"conditions_summary":"## Summary\n\nAn uncontrolled-resource-consumption vulnerability (CWE-400) in the Twisted HTTP/2 server lets any unauthenticated remote client exhaust server CPU over a single connection. A client that sends a request header block with `END_STREAM` and then immediately resets the stream makes the server route and render the request before it processes the reset. Reset streams are freed and never count against the concurrent-stream limit, and no reset-rate limiter exists, so the pattern can be repeated at line rate on one connection. This is the HTTP/2 Rapid Reset class, CVE-2023-44487.\n\n## Details\n\nFor one received segment the h2 events are processed in order in `H2Connection.dataReceived`. A `HEADERS(END_STREAM)` followed by `RST_STREAM` yields `RequestReceived`, `StreamEnded`, then `StreamReset`, so the request is dispatched and rendered on stream end before the reset is handled:\n\n```python\n# src/twisted/web/_http2.py  (H2Connection.dataReceived)\nfor event in events:\n    if isinstance(event, h2.events.RequestReceived):\n        self._requestReceived(event)     # allocate the request\n    elif isinstance(event, h2.events.StreamEnded):\n        self._requestEnded(event)        # -> requ","public_affected_ranges":["<= 26.4.0"]}],"null_published_at":"2026-10-31T22:13:31.290Z","source_updated_at":"2026-10-29T16:41:06.000Z","source_disclosed_at":"2026-10-29T16:41:06.000Z","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":"2026-10-31T21:55:49.621Z"}],"next_cursor":null,"snapshot_revision":"42594"}