{"items":[{"id":"NVI-00008853","kind":"vulnerability","title":"rustls: An unauthenticated ServerHello poisons the per-name key-exchange record, so later ClientHellos carry only a classical X25519 share","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-w44r-93j7-qv28"],"plain_summary":"GitHub lists this reviewed advisory for rustls, rustls. 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-04b61931ebf511eb47b1666771e9707d"],"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":"2026-10-27T16:08:57.000Z","value":"3.7 low","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-04b61931ebf511eb47b1666771e9707d"}],"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-04b61931ebf511eb47b1666771e9707d","url":"https://github.com/advisories/GHSA-w44r-93j7-qv28","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-w44r-93j7-qv28","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T21:56:51.534Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-04b61931ebf511eb47b1666771e9707d"],"technology":"rustls","known_exclusions":[],"conditions_summary":"## Summary\n\nThe client records the server-selected key-exchange group per server name when it processes the ServerHello, before the server is authenticated. A network attacker can answer one connection attempt for a target name with a ServerHello that selects X25519 and close the connection. Later ClientHellos for that name carry one X25519 share while supported_groups still lists X25519MLKEM768 first. If the server accepts that share instead of sending a HelloRetryRequest, the handshake completes with classical key exchange only and no error.\n\nAn attacker that answers one connection attempt for the target name with a ServerHello selecting X25519 changes every later ClientHello of that client for that name, for as long as the entry stays in the store. No certificate or completed handshake is needed: it parses the ClientHello, sends the ServerHello, and closes.\n\nTLS 1.3 transcript binding stops an on-path attacker from editing the ClientHello of one connection. It does not stop the attacker from steering the client's prediction state beforehand, because that state is written from an unauthenticated message.\n\n## What does not trigger it\n\n- Servers that send a HelloRetryRequest. The c","public_affected_ranges":["< 0.23.46"]},{"certainty":"source_listed","source_ids":["sr-04b61931ebf511eb47b1666771e9707d"],"technology":"rustls","known_exclusions":[],"conditions_summary":"## Summary\n\nThe client records the server-selected key-exchange group per server name when it processes the ServerHello, before the server is authenticated. A network attacker can answer one connection attempt for a target name with a ServerHello that selects X25519 and close the connection. Later ClientHellos for that name carry one X25519 share while supported_groups still lists X25519MLKEM768 first. If the server accepts that share instead of sending a HelloRetryRequest, the handshake completes with classical key exchange only and no error.\n\nAn attacker that answers one connection attempt for the target name with a ServerHello selecting X25519 changes every later ClientHello of that client for that name, for as long as the entry stays in the store. No certificate or completed handshake is needed: it parses the ClientHello, sends the ServerHello, and closes.\n\nTLS 1.3 transcript binding stops an on-path attacker from editing the ClientHello of one connection. It does not stop the attacker from steering the client's prediction state beforehand, because that state is written from an unauthenticated message.\n\n## What does not trigger it\n\n- Servers that send a HelloRetryRequest. The c","public_affected_ranges":[">= 0.24.0-dev.1, < 0.24.0-dev.2"]}],"null_published_at":"2026-10-31T22:13:27.119Z","source_updated_at":"2026-10-27T16:08:57.000Z","source_disclosed_at":"2026-10-27T16:08:54.000Z","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":"2026-10-31T21:56:51.534Z"}],"next_cursor":null,"snapshot_revision":"42594"}