---
cve: "CVE-2026-54590"
severity: "MEDIUM"
cvss: 5.9
epss: "29%"
vendor: "ronf"
kev: false
exploited: false
published: "2026-07-08 20:36:45"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-10T04:19:41+02:00"
---

# CVE-2026-54590

> 5.9 MEDIUM · 🧪 PoC

## Beschreibung

AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python asyncio framework. Version 2.23.0 contains an incomplete fix for CVE-2026-45309 in SSHServerConfig._set_tokens that blocks /, , and .. before %u substitution in AuthorizedKeysFile but does not block a leading ~ or ${ENV}, allowing later expansion in _expand_val and Path(filename).expanduser() to escape the intended authorized-keys directory. This issue is fixed in version 2.23.1.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 3d515ba9ba0cd9990d248bdf62bcf05d51261a88 (Commit)
- 1b5839f3827f7bf546fc311cc8da77788a9d22f7 (Commit)

## Referenzen

- <https://github.com/ronf/asyncssh/security/advisories/GHSA-qr67-gv47-xwwh>
- <https://github.com/ronf/asyncssh/commit/3d515ba9ba0cd9990d248bdf62bcf05d51261a88>
- <https://github.com/ronf/asyncssh/releases/tag/v2.23.1>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-54590) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_