---
cve: "CVE-2020-15133"
severity: "HIGH"
cvss: 8.0
epss: "0.9%"
vendor: "faye"
kev: false
exploited: false
published: "2020-07-31 17:40:21"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T14:48:58+02:00"
---

# CVE-2020-15133

> 8.0 HIGH · 🧪 PoC

## Beschreibung

In faye-websocket before version 0.11.0, there is a lack of certification validation in TLS handshakes. The `Faye::WebSocket::Client` class uses the `EM::Connection#start_tls` method in EventMachine to implement the TLS handshake whenever a `wss:` URL is used for the connection. This method does not implement certificate verification by default, meaning that it does not check that the server presents a valid and trusted TLS certificate for the expected hostname. That means that any `wss:` connection made using this library is vulnerable to a man-in-the-middle attack, since it does not confirm the identity of the server it is connected to. For further background information on this issue, please see the referenced GitHub Advisory. Upgrading `faye-websocket` to v0.11.0 is recommended.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- dc392490a8e84b9735aab0e306a2b477a6e84ce5 (Commit)

## Referenzen

- <https://blog.jcoglan.com/2020/07/31/missing-tls-verification-in-faye/>
- <https://github.com/faye/faye-websocket-ruby/security/advisories/GHSA-2v5c-755p-p4gv>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2020-15133) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_