---
cve: "CVE-2026-73430"
severity: "MEDIUM"
cvss: 5.3
epss: "33%"
vendor: "Eugeny"
kev: false
exploited: false
published: "2026-08-12 21:17:41"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-18T05:42:12+02:00"
---

# CVE-2026-73430

> 5.3 MEDIUM · 🧪 PoC

## Beschreibung

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-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Gering | warn |

## Patch verfügbar (OSV)

- a7fc1eb5717264e31c3c5f7dd849b73989a08f3d (Commit)
- 0089c89c94753bebbec12b956c07a1cd38740379 (Commit)

## Referenzen

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

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-73430) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_