CVE-2026-39903: 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-charact
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.
Details
Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-39903
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-399030.33% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 25% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-39903 | coverage & exploitation status | NVD · CVE.org |
More from NVD Recent CVEs
- unknownCVE-2026-57828: The Joomla extension Phoca Downloads is vulnerable to an authenticated arbitrary file upload t…2026-07-11
- unknownCVE-2026-57827: The Joomla extension RSFiles is vulnerable to an unauthenticated arbitrary file upload that al…2026-07-11
- highCVE-2026-1359: The Genolve – AI image AI video generation plugin for WordPress is vulnerable to unauthorized m…2026-07-11
- highCVE-2026-9282: The W3 Total Cache plugin for WordPress is vulnerable to Directory Traversal in all versions up…2026-07-11
- mediumCVE-2026-9017: The NEX-Forms – Ultimate Forms Plugin for WordPress plugin for WordPress is vulnerable to autho…2026-07-11