Server-Side Request Forgery (SSRF) in Flarum - CVE-2023-40033
Published: August 16, 2023 / Updated: April 20, 2026
Vulnerability identifier: #VU126533
CSH Severity: Low
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2023-40033
CWE-ID: CWE-918
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Flarum
Flarum
Software vendor:
Flarum
Flarum
Description
The vulnerability allows a remote user to disclose local file contents or conduct a blind server-side request forgery attack.
The vulnerability exists due to server-side request forgery in the avatar upload handling through the intervention/image package when processing an uploaded file whose contents are interpreted as a URL after MIME type spoofing. A remote user can upload a crafted file with a spoofed MIME type to disclose local file contents or conduct a blind server-side request forgery attack.
Remediation
Install security update from vendor's website.