CVE-2026-102821
CVE-2026-102821 · Russh: Unbounded memory exhaustion via CHANNEL_OPEN flood during a client-stalled rekey
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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.
CVSS 6.5 · Medium · EPSS 0.4% · Fix available
- Published
- Updated
Stack: system
Affected products and versions
russh
- Versions
- < 0.63.2: Affected
No fix published
rust-russh Debian:14
- Versions
- 0.57.1-1
- 0.57.1-2
- Affected ranges
- ECOSYSTEM: < 0.64.1-1
Update to 0.64.1-1
rust-russh Ubuntu:26.10
- Versions
- 0.57.1-2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published