CVE-2026-73430 Russh: Pre-auth remote panic via all-zero Curve25519 peer public value (encode_mpint OOB)

Russh is a Rust SSH client & server library. Prior to 0.62.4, an unauthenticated SSH client can cause a denial of service by sending SSHMSGKEXECDHINIT with a 32-byte all-zero QC value. Curve25519Kex::serverdh in russh/src/kex/curve25519.rs accepts the all-zero peer public value and computes an...

CVE-2026-73430

Russh (Rust SSH client/server library) before version 0.62.4 is affected. An unauthenticated SSH client can trigger a denial of service by sending SSH_MSG_KEX_ECDH_INIT with a 32-byte all-zero Q_C value. In Curve25519Kex::server_dh, the all-zero peer public value is accepted, leading to a zero sh...