CVE-2026-73430
Russh: Pre-auth remote panic via all-zero Curve25519 peer public value (encode_mpint OOB)
- State
- Published
- Severity
- 5.3 Medium
- Published
- Aug 12, 2026
- Updated
- Aug 13, 2026
- Reserved
- Aug 12, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.3 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | GitHub_M |
Weaknesses
- CWE-754 Improper Check for Unusual or Exceptional Conditions
Affected Products
| Product | Versions |
|---|---|
russhEugeny |
|
References
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