CVE-2026-73429

MEDIUM 5.3

Russh: client wrong-length X25519 `clone_from_slice` panic (pre-auth DoS)

CVSS Score

5.3

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-704 CWE-754
Vendor	eugeny
Product	russh
Published	Aug 12, 2026

Stay Ahead of the Next One

Get instant alerts for eugeny russh

Be the first to know when new medium vulnerabilities affecting eugeny russh are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Affected Versions

Eugeny / russh

< 0.62.4

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/Eugeny/russh/security/advisories/GHSA-g9hv-x236-4qp3 github.com: https://github.com/Eugeny/russh/commit/a7fc1eb5717264e31c3c5f7dd849b73989a08f3d github.com: https://github.com/Eugeny/russh/releases/tag/v0.62.4