Russh: Missing X25519 zero-point validation in hybrid ML-KEM key exchange
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.
CVE-2026-102824
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-102824
russh
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "Eugeny",
"product": "russh",
"versions": [
{
"status": "affected",
"version": "< 0.63.0"
}
]
}
]- Related CVEs
- CVE-2026-102824
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #4943 · Revision 1
- Added to Heist Feed
- Publisher date