CVE-2026-39903

Summary

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.

Affected Software

VendorProductVersion RangeStatus
SimpleMachinesSMF2.1.0 < 2.1.8affected
SimpleMachinesSMF3.0.0 < 3.0.0 Alpha 5affected

Weaknesses

  • CWE-863: Incorrect Authorization

References