CVE-2026-73429: Eugeny Russh

Medium severity, CVSS 5.3. EPSS: 0.5% chance of exploitation in the next 30 days.

Russh is a Rust SSH client & server library. Prior to 0.62.4, a malicious SSH server can crash a russh client session with a malformed KEX_ECDH_REPLY containing a server ephemeral value that is not 32 bytes long. The client-side Curve25519Kex::compute_shared_secret function in russh/src/kex/curve25519.rs passes the decoded exchange.server_ephemeral value to clone_from_slice without validating its length, causing a deterministic panic before the server host key is verified. The panic terminates the spawned client session task and surfaces as a JoinError, while the embedding process normally remains running. This issue is fixed in version 0.62.4.

Affected products

• Eugeny Russh: before 0.62.4 (fixed in 0.62.4)

Published 2026-08-12. Last modified 2026-09-09.