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.
Published: 2026-08-26
Score: 8.6 High
EPSS: < 1% Very Low
KEV: No
Impact: Privilege Escalation to Administrator
Action: Immediate Patch
AI Analysis

Impact

Simple Machines Forum preceding 2.1.7 contains an authorization state‑confusion flaw in the Profile::load() routine. An authenticated low‑privileged user can send a request that includes multiple values for the user parameter. Because the loader fails to reconcile the loaded profile ($member) with the currently authenticated user's ownership flag ($user->is_owner), the system mistakenly treats the targeted administrator profile as owned by the attacker. The result is that the attacker can change the administrator password and gain full account takeover control.

Affected Systems

All Simple Machines Forum installations running version 2.1.7 or earlier are affected. The vulnerability is fixed in commit 6f0dc61958aa86a4b436a222f6176812ed5bbb95; the fix is not included in SMF 2.1.7 but is available in newer releases that incorporate the patch.

Risk and Exploitability

The CVSS score of 8.6 categorizes this issue as high severity. Although an EPSS score is not available, the vulnerability does not appear in the CISA KEV catalog, indicating no confirmed widespread exploitation yet. Attackers must be authenticated with low privileges and have the ability to submit crafted profile requests. The attack is remote and can be triggered through the web interface, making it potentially exploitable without additional local access.

Generated by OpenCVE AI on August 27, 2026 at 00:05 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade to a Simple Machines Forum release that includes the fix from commit 6f0dc61958aa86a4b436a222f6176812ed5bbb95.
  • If an immediate upgrade is not possible, modify the Profile::load() logic to accept only a single user identifier and to verify that the loaded profile belongs to the authenticated user before allowing any administrative changes.
  • Implement monitoring of web logs for repeated multi‑value user requests and apply network or application‑level blocking for suspicious traffic originating from low‑privileged accounts.

Generated by OpenCVE AI on August 27, 2026 at 00:05 UTC.

Tracking

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Advisories

No advisories yet.

History

Fri, 28 Aug 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Fri, 28 Aug 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 0, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:N'}

 cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'}

Thu, 27 Aug 2026 01:15:00 +0000

Type Values Removed Values Added
First Time appeared Simplemachines
Simplemachines smf
Vendors & Products Simplemachines
Simplemachines smf

Wed, 26 Aug 2026 22:00:00 +0000

Type Values Removed Values Added
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.
Title Simple Machines Forum < 2.1.7 Authorization Confusion via Profile::load()
Weaknesses CWE-863
References
Metrics cvssV3_1

{'score': 0, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:N'}

cvssV4_0

{'score': 8.6, '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'}

Subscriptions

Simplemachines Smf
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-28T16:00:22.892Z

Reserved: 2026-05-01T18:22:45.640Z

Link: CVE-2026-43621

cve-icon Vulnrichment

Updated: 2026-08-27T18:24:16.669Z

cve-icon NVD

Status : Received

Published: 2026-08-26T22:16:24.643

Modified: 2026-08-28T20:17:31.290

Link: CVE-2026-43621

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-27T01:00:04Z

Weaknesses