What’s Vulnerable › Vulnerabilities

CVE-2026-43621: Simple Machines Forum < 2.1.7 Authorization Confusion via Profile::load()

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-26 · updated 2026-09-24
• Weakness: CWE-863

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

• SimpleMachines SMF: through 2.1.7

References

• https://github.com/SimpleMachines/SMF/commit/6f0dc61958aa86a4b436a222f6176812ed5bbb95
• https://www.vulncheck.com/advisories/simple-machines-forum-authorization-confusion-via-profile-load

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