CVE-2026-102821

Medium

Description

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.

SeverityMedium

CVSS6.5

Exploit probability—

ProductEugeny Russh

PublishedSep 29, 2026

First seenSep 29, 2026

Weakness typeCWE-400Uncontrolled resource consumption CWE-770Allocation of resources without limits

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

Product	Affected versions	Fixed in
Eugeny russh	< 0.63.2	—

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