Description
Russh is a Rust SSH client & server library. Prior to 0.62.4, a malicious SSH server can crash a russh client session with a malformed KEX_ECDH_REPLY containing a server ephemeral value that is not 32 bytes long. The client-side Curve25519Kex::compute_shared_secret function in russh/src/kex/curve25519.rs passes the decoded exchange.server_ephemeral value to clone_from_slice without validating its length, causing a deterministic panic before the server host key is verified. The panic terminates the spawned client session task and surfaces as a JoinError, while the embedding process normally remains running. This issue is fixed in version 0.62.4.
Published: 2026-08-12
Score: 5.3 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-g9hv-x236-4qp3 Russh: client wrong-length X25519 `clone_from_slice` panic (pre-auth DoS)
History

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, a malicious SSH server can crash a russh client session with a malformed KEX_ECDH_REPLY containing a server ephemeral value that is not 32 bytes long. The client-side Curve25519Kex::compute_shared_secret function in russh/src/kex/curve25519.rs passes the decoded exchange.server_ephemeral value to clone_from_slice without validating its length, causing a deterministic panic before the server host key is verified. The panic terminates the spawned client session task and surfaces as a JoinError, while the embedding process normally remains running. This issue is fixed in version 0.62.4.
Title Russh: client wrong-length X25519 `clone_from_slice` panic (pre-auth DoS)
Weaknesses CWE-704
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'}

Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-12T20:53:19.558Z

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

Link: CVE-2026-73429

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-12T21:17:41.750

Modified: 2026-08-12T21:17:41.750

Link: CVE-2026-73429

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses
  • CWE-704

    Incorrect Type Conversion or Cast

  • CWE-754

    Improper Check for Unusual or Exceptional Conditions