Is CVE-2023-40033 actively exploited?

No active exploitation of CVE-2023-40033 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2023-40033 be exploited remotely?

Yes. CVE-2023-40033 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2023-40033?

CVE-2023-40033 has a CVSS score of 7.1 (HIGH).

HOME VULNERABILITIESCVE-2023-40033

HIGH

CVE-2023-40033

CWE-918Published: August 16, 2023· Updated: Jun 17, 2026

7.1

CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2023-40033 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 7.1.