---
id: CVE-2026-102824
title: Russh is a Rust SSH client and server library
summary: >-
  Russh is a Rust SSH client and server library. Prior to 0.63.0, the hybrid
  ML-KEM 768 and X25519 implementation in russh/src/kex/hybrid_mlkem.rs accepts
  an all-zero 32-byte peer X25519 public key in both server_dh and
  compute_shared_secr…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'
cwe:
  - CWE-327
vendor: Eugeny
product: russh
affected:
  - russh < 0.63.0
published: '2026-09-29'
updated: '2026-09-29'
sourceUpdated: '2026-09-29T19:17:24.673'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-102824'
references:
  - url: >-
      https://github.com/Eugeny/russh/commit/8da8967f196472576b1565d518a0ed60fce60f0c
    label: security-advisories@github.com
  - url: 'https://github.com/Eugeny/russh/releases/tag/v0.63.0'
    label: security-advisories@github.com
  - url: 'https://github.com/Eugeny/russh/security/advisories/GHSA-w3jg-pjxf-73p4'
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-29T18:42:35.834Z'
---

## Overview

Russh is a Rust SSH client and server library. Prior to 0.63.0, the hybrid ML-KEM 768 and X25519 implementation in russh/src/kex/hybrid_mlkem.rs accepts an all-zero 32-byte peer X25519 public key in both server_dh and compute_shared_secret, forcing the X25519 contribution to the combined shared secret to zero. A malicious SSH peer can therefore make the combined secret depend only on ML-KEM, defeating the hybrid exchange's intended fallback protection if ML-KEM is later weakened. This issue is fixed in version 0.63.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.