Vulnerability in Eugeny Russh

CVE-2026-102824

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.

Vulnerability class: POODLE (CVE-2014-3566)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-102824?
CVE-2026-102824 is a medium-severity vulnerability in Eugeny Russh, classified under Use of a Broken or Risky Cryptographic Algorithm. CVSS score: 4.3/10. Published 2026-09-29.
How severe is CVE-2026-102824?
Medium severity. CVSS v3 base score is 4.3 out of 10.