{"id":"UBUNTU-CVE-2026-116774","details":"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.","modified":"2026-10-28T20:17:46.299078666Z","published":"2026-10-27T21:18:00Z","upstream":["CVE-2026-116774"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-116774"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-116774"},{"type":"REPORT","url":"https://github.com/Eugeny/russh/security/advisories/GHSA-fw5c-8223-6h42"},{"type":"REPORT","url":"https://github.com/Eugeny/russh/commit/39cb9dbaa37caf555d34c6c22efa3bbbff9e186c"},{"type":"REPORT","url":"https://github.com/Eugeny/russh/releases/tag/v0.65.0"}],"affected":[{"package":{"name":"rust-russh","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/rust-russh?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.57.1-2"],"ecosystem_specific":{"binaries":[{"binary_version":"0.57.1-2","binary_name":"librust-russh-dev"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-116774.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"},{"type":"Ubuntu","score":"medium"}]}