{"id":"CVE-2026-116774","aliases":[],"title":"russh: peer-declared zero maximum packet size permanently stalls channel writes (silent AsyncWrite hang)","titleSource":"GitHub_M","descriptionSource":"GitHub_M","products":[{"vendor":"Eugeny","name":"russh","platforms":[],"versions":[{"version":">= 0.60.0, < 0.65.0","status":"affected"}],"source":"GitHub_M","url":"https://www.cve.org/CVERecord?id=CVE-2026-116774"}],"remediation":[],"description":"russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. From 0.60.0 until 0.65.0, channel-open parsing accepts a peer-declared maximum_packet_size of zero and passes it into ChannelTx::poll_writable in russh/src/channels/io/tx.rs. The Channel::data, Channel::make_writer, and Channel::into_stream asynchronous write paths then calculate a writable size of zero and remain pending forever because window adjustments cannot satisfy a static zero packet maximum. An authenticated client can strand server writes, and a malicious server can strand client writes, allowing affected tasks, channels, and connections to accumulate without surfacing an error. This issue is fixed in version 0.65.0.","severity":"medium","score":4.3,"published":"2026-10-27T20:25:26.914Z","modified":"2026-10-28T16:13:18.607Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://github.com/Eugeny/russh/security/advisories/GHSA-fw5c-8223-6h42","https://github.com/Eugeny/russh/commit/39cb9dbaa37caf555d34c6c22efa3bbbff9e186c","https://github.com/Eugeny/russh/releases/tag/v0.65.0"],"sources":[{"name":"CVE","id":"CVE-2026-116774","modified":"2026-10-28T16:13:18.607Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-116774"}],"assessments":[{"source":"GitHub_M","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","score":4.3}],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-29T03:15:31.428Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}