CVE-2026-102821
Russh: Unbounded memory exhaustion via CHANNEL_OPEN flood during a client-stalled rekey
MEDIUM 6.5EPSS 0.3%
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.
- Affected
- Eugeny · russh
- CVSS v3.1 GITHUB
- 6.5 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.29% chance of exploitation in the next 30 days, 21st percentile
- Published
- 2026-09-29
- Updated
- 2026-09-30