CVE-2026-102824

medium

Description

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.

References

https://github.com/Eugeny/russh/security/advisories/GHSA-w3jg-pjxf-73p4

https://github.com/Eugeny/russh/releases/tag/v0.63.0

https://github.com/Eugeny/russh/commit/8da8967f196472576b1565d518a0ed60fce60f0c

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-89207

Details

Source: Mitre, NVD

Published: 2026-09-29

Updated: 2026-09-30

Risk Information

CVSS v2

Base Score: 4

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

Severity: Medium

CVSS v3

Base Score: 4.3

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

Severity: Medium

EPSS

EPSS: 0.00141