CVE-2026-102821: Eugeny Russh

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

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 products

• Eugeny Russh: before 0.63.2 (fixed in 0.63.2)

Published 2026-09-29. Last modified 2026-09-30.