Vulnerability · Published Aug 26, 2026 · Assigned by VulnCheck
CVE-2026-43621Simple Machines Forum < 2.1.7 Authorization Confusion via Profile::load()
High 8.1
In plain English
A high-severity incorrect authorization in SMF from SimpleMachines. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
Simple Machines Forum (SMF) through 2.1.7, fixed in commit 6f0dc61, contains an authorization state-confusion vulnerability in the profile loader that allows authenticated low-privileged users to gain administrator access by supplying multiple values for the user parameter. Attackers can exploit the mismatch between Profile::$member and User::$me->is_owner during sequential profile loading to be treated as the owner of an administrator profile, enabling unauthorized password changes and full account takeover.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| SimpleMachines | SMF | 0 – through 2.1.7 |
Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N