{"items":[{"id":"NVI-00009191","kind":"vulnerability","title":"russh: peer-declared zero maximum packet size permanently stalls channel writes (silent AsyncWrite hang)","revision":3,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-fw5c-8223-6h42","CVE-2026-116774"],"plain_summary":"GitHub lists this reviewed advisory for russh. 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-1f0a3e8d90a6c0dc284434ec0f7dab29"],"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":"2026-10-30T22:58:55.000Z","value":"4.3 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-ea6c25c07d9401726ec666ee0ef9e1c2"},{"kind":"EPSS","as_of":"2026-11-03T12:00:27.000Z","value":"0.259%","meaning":"FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.17707. Missing scores are unknown.","source_id":"sr-1f0a3e8d90a6c0dc284434ec0f7dab29"}],"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-ea6c25c07d9401726ec666ee0ef9e1c2","url":"https://github.com/advisories/GHSA-fw5c-8223-6h42","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-fw5c-8223-6h42","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T21:55:49.621Z"},{"id":"sr-1f0a3e8d90a6c0dc284434ec0f7dab29","url":"https://www.first.org/epss/data.html","basis":"official_catalog","notes":"FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.","title":"CVE-2026-116774","publisher":"FIRST EPSS","observed_at":"2026-11-03T17:44:07.777Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-ea6c25c07d9401726ec666ee0ef9e1c2"],"technology":"russh","known_exclusions":[],"conditions_summary":"## Summary\n\nA peer can advertise `maximum packet size = 0` in its channel-open message (`CHANNEL_OPEN` when attacking a server, `CHANNEL_OPEN_CONFIRMATION` when attacking a client). russh accepts the value without validation and copies it into the channel write state, where it caps the size of every outgoing data chunk. In the `AsyncWrite` code path (`ChannelTx::poll_writable`, used by `Channel::data()`, `Channel::make_writer()` and `Channel::into_stream()`), a cap of 0 makes every write future stay `Poll::Pending` forever: `writable = max_packet_size.min(window_size).min(buf_len)` is always 0, and no future event can ever raise it (a static maximum packet size of 0 can never be satisfied by any amount of peer-granted window). The write neither completes nor errors, so the application task hangs silently.\n\nEvery other write path in russh already treats `max_packet_size == 0` as an error (`Error::Inconsistent`): `Channel::reserve_writable_chunk` (`russh/src/channels/mod.rs:363-365`) and the session packetizers (`russh/src/session.rs:489-492` and `549-552`). The `AsyncWrite` path is the only one that lacks the guard - it contradicts the crate's own invariant.\n\n## Root cause\n\n(1) Peer","public_affected_ranges":[">= 0.60.0, <= 0.64.1"]}],"null_published_at":"2026-11-07T14:01:55.419Z","source_updated_at":"2026-10-30T22:58:55.000Z","source_disclosed_at":"2026-10-30T22:58:53.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.","null_first_observed_at":"2026-10-31T21:55:49.621Z"},{"id":"NVI-00009191","kind":"vulnerability","title":"russh: peer-declared zero maximum packet size permanently stalls channel writes (silent AsyncWrite hang)","revision":2,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-fw5c-8223-6h42","CVE-2026-116774"],"plain_summary":"GitHub lists this reviewed advisory for russh. 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-c21f61d48677ae8a0deb7d64b28d249a"],"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":"2026-10-30T22:58:55.000Z","value":"4.3 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-ea6c25c07d9401726ec666ee0ef9e1c2"},{"kind":"EPSS","as_of":"2026-10-31T12:00:27.000Z","value":"0.259%","meaning":"FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.17692. Missing scores are unknown.","source_id":"sr-c21f61d48677ae8a0deb7d64b28d249a"}],"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-ea6c25c07d9401726ec666ee0ef9e1c2","url":"https://github.com/advisories/GHSA-fw5c-8223-6h42","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-fw5c-8223-6h42","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T21:55:49.621Z"},{"id":"sr-c21f61d48677ae8a0deb7d64b28d249a","url":"https://www.first.org/epss/data.html","basis":"official_catalog","notes":"FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.","title":"CVE-2026-116774","publisher":"FIRST EPSS","observed_at":"2026-10-31T22:06:15.374Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-ea6c25c07d9401726ec666ee0ef9e1c2"],"technology":"russh","known_exclusions":[],"conditions_summary":"## Summary\n\nA peer can advertise `maximum packet size = 0` in its channel-open message (`CHANNEL_OPEN` when attacking a server, `CHANNEL_OPEN_CONFIRMATION` when attacking a client). russh accepts the value without validation and copies it into the channel write state, where it caps the size of every outgoing data chunk. In the `AsyncWrite` code path (`ChannelTx::poll_writable`, used by `Channel::data()`, `Channel::make_writer()` and `Channel::into_stream()`), a cap of 0 makes every write future stay `Poll::Pending` forever: `writable = max_packet_size.min(window_size).min(buf_len)` is always 0, and no future event can ever raise it (a static maximum packet size of 0 can never be satisfied by any amount of peer-granted window). The write neither completes nor errors, so the application task hangs silently.\n\nEvery other write path in russh already treats `max_packet_size == 0` as an error (`Error::Inconsistent`): `Channel::reserve_writable_chunk` (`russh/src/channels/mod.rs:363-365`) and the session packetizers (`russh/src/session.rs:489-492` and `549-552`). The `AsyncWrite` path is the only one that lacks the guard - it contradicts the crate's own invariant.\n\n## Root cause\n\n(1) Peer","public_affected_ranges":[">= 0.60.0, <= 0.64.1"]}],"null_published_at":"2026-11-06T21:03:48.015Z","source_updated_at":"2026-10-30T22:58:55.000Z","source_disclosed_at":"2026-10-30T22:58:53.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.","null_first_observed_at":"2026-10-31T21:55:49.621Z"},{"id":"NVI-00009191","kind":"vulnerability","title":"russh: peer-declared zero maximum packet size permanently stalls channel writes (silent AsyncWrite hang)","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-fw5c-8223-6h42","CVE-2026-116774"],"plain_summary":"GitHub lists this reviewed advisory for russh. 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-ea6c25c07d9401726ec666ee0ef9e1c2"],"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":"2026-10-30T22:58:55.000Z","value":"4.3 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-ea6c25c07d9401726ec666ee0ef9e1c2"}],"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-ea6c25c07d9401726ec666ee0ef9e1c2","url":"https://github.com/advisories/GHSA-fw5c-8223-6h42","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-fw5c-8223-6h42","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T21:55:49.621Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-ea6c25c07d9401726ec666ee0ef9e1c2"],"technology":"russh","known_exclusions":[],"conditions_summary":"## Summary\n\nA peer can advertise `maximum packet size = 0` in its channel-open message (`CHANNEL_OPEN` when attacking a server, `CHANNEL_OPEN_CONFIRMATION` when attacking a client). russh accepts the value without validation and copies it into the channel write state, where it caps the size of every outgoing data chunk. In the `AsyncWrite` code path (`ChannelTx::poll_writable`, used by `Channel::data()`, `Channel::make_writer()` and `Channel::into_stream()`), a cap of 0 makes every write future stay `Poll::Pending` forever: `writable = max_packet_size.min(window_size).min(buf_len)` is always 0, and no future event can ever raise it (a static maximum packet size of 0 can never be satisfied by any amount of peer-granted window). The write neither completes nor errors, so the application task hangs silently.\n\nEvery other write path in russh already treats `max_packet_size == 0` as an error (`Error::Inconsistent`): `Channel::reserve_writable_chunk` (`russh/src/channels/mod.rs:363-365`) and the session packetizers (`russh/src/session.rs:489-492` and `549-552`). The `AsyncWrite` path is the only one that lacks the guard - it contradicts the crate's own invariant.\n\n## Root cause\n\n(1) Peer","public_affected_ranges":[">= 0.60.0, <= 0.64.1"]}],"null_published_at":"2026-10-31T22:13:31.289Z","source_updated_at":"2026-10-30T22:58:55.000Z","source_disclosed_at":"2026-10-30T22:58:53.000Z","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"}