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.

References

https://github.com/Eugeny/russh/security/advisories/GHSA-35g8-35p8-c8fw

https://github.com/Eugeny/russh/releases/tag/v0.63.2

https://github.com/Eugeny/russh/commit/a282af361ac99bc76b80876d1aae128e89dbf66b

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-89204

Details

Source: Mitre, NVD

Published: 2026-09-29

Updated: 2026-09-30

Named Vulnerability: GHSA-35g8-35p8-c8fw

Risk Information

CVSS v2

Base Score: 6.8

Vector: CVSS2#AV:N/AC:L/Au:S/C:N/I:N/A:C

Severity: Medium

CVSS v3

Base Score: 6.5

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Severity: Medium

EPSS

EPSS: 0.00295