---
cve: "CVE-2023-40033"
severity: "HIGH"
cvss: 7.1
epss: "50%"
vendor: "flarum"
kev: false
exploited: false
published: "2023-08-16 21:15:09"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-13T06:49:58+02:00"
---

# CVE-2023-40033

> 7.1 HIGH · 🧪 PoC

## Beschreibung

Flarum is an open source forum software. Flarum is affected by a vulnerability that allows an attacker to conduct a Blind Server-Side Request Forgery (SSRF) attack or disclose any file on the server, even with a basic user account on any Flarum forum. By uploading a file containing a URL and spoofing the MIME type, an attacker can manipulate the application to execute unintended actions. The vulnerability is due to the behavior of the `intervention/image` package, which attempts to interpret the supplied file contents as a URL, which then fetches its contents. This allows an attacker to exploit the vulnerability to perform SSRF attacks, disclose local file contents, or conduct a blind oracle attack. This has been patched in Flarum version 1.8.0. Users are advised to upgrade. Users unable to upgrade may disable PHP's `allow_url_fopen` which will prevent the fetching of external files via URLs as a temporary workaround for the SSRF aspect of the vulnerability.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- d27f9525847212fedd555ed165a2eb80bca17328 (Commit)
- d1059c1cc79fe61f9538f3da55e8f42abbede570 (Commit)

## Referenzen

- <https://github.com/flarum/framework/security/advisories/GHSA-67c6-q4j4-hccg>
- <https://github.com/flarum/framework/commit/d1059c1cc79fe61f9538f3da55e8f42abbede570>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2023-40033) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_