CVE-2026-73430: medium-severity vulnerability in Eugeny russh
Russh: Pre-auth remote panic via all-zero Curve25519 peer public value (encode_mpint OOB)
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.3epss 0.6%
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 SSH_MSG_KEX_ECDH_INIT with a 32-byte all-zero Q_C value. Curve25519Kex::server_dh in russh/src/kex/curve25519.rs accepts the all-zero peer public value and computes an all-zero shared secret, after which compute_exchange_hash calls encode_mpint in russh/src/kex/mod.rs and indexes beyond the end of the input while skipping leading zero bytes. The resulting panic occurs before authentication and terminates the server key-exchange task. This issue is fixed in version 0.62.4.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Affected products
Eugeny · russhRelated CVEs — Eugeny russh
In the same product, most dangerous first.
CVE-2024-43410HIGHRussh has an OOM Denial of Service due to allocation of untrusted amountEPSS 0.9%CVE-2026-73429MEDIUMRussh: client wrong-length X25519 `clone_from_slice` panic (pre-auth DoS)EPSS 0.5%CVE-2026-42189HIGHRussh: Pre-auth DoS via unbounded allocation in keyboard-interactive authEPSS 0.5%CVE-2026-73489MEDIUMRussh: Post-auth remote panic via pty-req with more than 130 terminal-mode recordsEPSS 0.5%CVE-2025-54804MEDIUMRussh is missing an overflow check during channel windows adjustEPSS 0.4%CVE-2026-68930MEDIUMRussh: Channel-scoped server callbacks can be reached without an open channelEPSS 0.4%