CVE-2026-39903

Description

Simple Machines Forum 2.1 prior to commit 7d048f8 and 3.0 prior to commit a7875e8 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.

References

https://www.vulncheck.com/advisories/simple-machines-forum-authorization-bypass-via-attachmentapprove-php

https://github.com/SimpleMachines/SMF/pull/9182

https://github.com/SimpleMachines/SMF/pull/9181

https://github.com/SimpleMachines/SMF/commit/a7875e876a647572dd4c45da881b875092caac3d

https://github.com/SimpleMachines/SMF/commit/7d048f8d66aab9af51cd6ee110fbad103cf673e8

Details

Source: Mitre, NVD

Risk Information

CVSS v2

CVSS v3

CVSS v4

EPSS