github.com
https://github.com/Eugeny/russh CVE-2026-73430
MEDIUM
Russh: Pre-auth remote panic via all-zero Curve25519 peer public value (encode_mpint OOB)
Record summary
CVE-2026-73430 has a selected CVSS score of 5.3 (medium).
Description
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.
Description source: CVE List
Exploitation context
CISA SSVC decision
ExploitationNone
AutomatableYes
Technical impactPartial
CISA Coordinator · SSVC 2.0.3 · Evaluated Aug 13, 2026 · Source: CVE List
Affected products and versions
2| Product | Source | Version range | Status |
|---|---|---|---|
| CVE List | < 0.62.4 | affected | |
| GitHub Advisory | Before 0.62.4 · Fixed in 0.62.4 | affected |
References
4github.com
https://github.com/Eugeny/russh/commit/a7fc1eb5717264e31c3c5f7dd849b73989a08f3d github.com
https://github.com/Eugeny/russh/releases/tag/v0.62.4 github.comConfirmation
https://github.com/Eugeny/russh/security/advisories/GHSA-5xvq-cp9x-6p6r