CVE-2026-43621

High

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.

SeverityHigh

CVSS8.1

Exploit probability—

ProductSMF

PublishedAug 26, 2026

First seenAug 26, 2026

Weakness typeCWE-863Incorrect authorization

How to fix

Patches

github.com/SimpleMachines/SMF/commit/6f0dc61958aa86a4b436a222f6176812ed5bbb95

Affected products

Product	Affected versions	Fixed in
SimpleMachines SMF	v ≤ 2.1.7	—

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