CVE-2026-73430

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 v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://github.com/Eugeny/russh/commit/a7fc1eb5717264e31c3c5f7dd849b73989a08f3d
https://github.com/Eugeny/russh/releases/tag/v0.62.4
https://github.com/Eugeny/russh/security/advisories/GHSA-5xvq-cp9x-6p6r

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-12 21:17

Updated : 2026-09-09 21:02

NVD link : CVE-2026-73430

Mitre link : CVE-2026-73430

CVE.ORG link : CVE-2026-73430

JSON object : View

Products Affected

No product.

CWE

CWE-754

Improper Check for Unusual or Exceptional Conditions

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