Simple Machines Forum 2.1 prior to 2.1.8 and 3.0 prior to 3.0 Alpha 5 contains an authorization bypass vulnerability in Sources/Actions/AttachmentApprove.php where a single-character operator error causes the permission check to always pass regardless of user permissions. An authenticated low-privileged user can approve, reject, or delete any pending attachments on any board without holding the required approve_posts permission, bypass moderation queues for their own uploads, and enumerate and delete other users' pending attachments.
History

Tue, 14 Jul 2026 02:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Fri, 10 Jul 2026 19:00:00 +0000

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

Fri, 10 Jul 2026 16:30:00 +0000

Type Values Removed Values Added
Description Simple Machines Forum 2.1 prior to 2.1.8 and 3.0 prior to 3.0 Alpha 5 contains an authorization bypass vulnerability in Sources/Actions/AttachmentApprove.php where a single-character operator error causes the permission check to always pass regardless of user permissions. An authenticated low-privileged user can approve, reject, or delete any pending attachments on any board without holding the required approve_posts permission, bypass moderation queues for their own uploads, and enumerate and delete other users' pending attachments.
Title Simple Machines Forum Authorization Bypass via AttachmentApprove.php
Weaknesses CWE-863
References
Metrics cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L'}

cvssV4_0

{'score': 7.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-07-10T16:03:20.983Z

Updated: 2026-07-14T01:57:00.927Z

Reserved: 2026-04-07T20:57:06.209Z

Link: CVE-2026-39903

cve-icon Vulnrichment

Updated: 2026-07-14T01:56:57.240Z

cve-icon NVD

No data.

cve-icon Redhat

No data.