{"id":"UBUNTU-CVE-2026-102821","details":"Russh is a Rust SSH client and server library. Prior to 0.63.2, an authenticated remote peer can send SSH_MSG_KEXINIT without the required SSH_MSG_KEX_ECDH_INIT and then flood SSH_MSG_CHANNEL_OPEN messages while SessionKexState::InProgress prevents priority_receiver in russh/src/server/session.rs from being drained. The server continues processing network input and enqueues a ChannelOpenReply for each request on an unbounded channel, allowing one connection to grow memory until the process is terminated. This issue is fixed in version 0.63.2.","modified":"2026-10-17T12:57:56.519278416Z","published":"2026-09-29T19:17:00Z","upstream":["CVE-2026-102821"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-102821"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-102821"},{"type":"REPORT","url":"https://github.com/Eugeny/russh/security/advisories/GHSA-35g8-35p8-c8fw"},{"type":"REPORT","url":"https://github.com/Eugeny/russh/commit/a282af361ac99bc76b80876d1aae128e89dbf66b"},{"type":"REPORT","url":"https://github.com/Eugeny/russh/releases/tag/v0.63.2"}],"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_name":"librust-russh-dev","binary_version":"0.57.1-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-102821.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}