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.

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Source ID Title
Github GHSA Github GHSA GHSA-5xvq-cp9x-6p6r Russh: Pre-auth remote panic via all-zero Curve25519 peer public value (encode_mpint OOB)
Fixes

Solution

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Workaround

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History

Wed, 12 Aug 2026 23:15:00 +0000

Type Values Removed Values Added
First Time appeared Eugeny
Eugeny russh
Vendors & Products Eugeny
Eugeny russh

Wed, 12 Aug 2026 21:00:00 +0000

Type Values Removed Values Added
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.
Title Russh: Pre-auth remote panic via all-zero Curve25519 peer public value (encode_mpint OOB)
Weaknesses CWE-754
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-12T20:55:38.202Z

Reserved: 2026-08-12T14:32:11.796Z

Link: CVE-2026-73430

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-12T21:17:41.883

Modified: 2026-08-12T21:17:41.883

Link: CVE-2026-73430

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-13T02:30:12Z

Weaknesses