{"id":"CVE-2023-40033","aliases":["GHSA-67c6-q4j4-hccg"],"url":"https://o3.security/vulnerability/CVE-2023-40033","summary":"Server-Side Request Forgery via Avatar upload in flarum","details":"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.","published":"2023-08-16T20:34:11.445Z","modified":"2026-08-12T03:51:46.596885511Z","cvss":{"score":7.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"flarum/core","fixedVersion":"1.8.0"},{"ecosystem":"Packagist","name":"flarum/framework","fixedVersion":"1.8.0"}],"fix":{"url":"https://github.com/flarum/framework/commit/d1059c1cc79fe61f9538f3da55e8f42abbede570","label":"flarum/framework@d1059c1"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/40xxx/CVE-2023-40033.json"},{"type":"ADVISORY","url":"https://github.com/flarum/framework/security/advisories/GHSA-67c6-q4j4-hccg"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-40033"},{"type":"FIX","url":"https://github.com/flarum/framework/commit/d1059c1cc79fe61f9538f3da55e8f42abbede570"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:46.596885511Z"}}