# Sensei LMS <= 4.26.4 - Authenticated (Subscriber+) Insecure Direct Object Reference to Other Users' Files via Quiz File Upload Answers

- **ID:** WPSEC-2026-2909
- **Plugin:** Sensei LMS – Online Courses, Quizzes, & Learning (`sensei-lms`), https://wordpress.org/plugins/sensei-lms/
- **Affected versions:** all versions before 4.27.0
- **Fixed in:** 4.27.0 (Update to 4.27.0 or later.)
- **Severity:** Medium 5.4 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N)
- **Weakness:** CWE-639
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-11-12)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/sensei-lms
- **Fix released:** 2026-11-10
- **Published:** 2026-11-12
- **URL:** https://wpsec.com/vuln/WPSEC-2026-2909/

## Description

The Sensei LMS plugin for WordPress is vulnerable to Insecure Direct Object Reference via quiz file upload answers in all versions up to, and including, 4.26.4. This is due to the quiz answer handler accepting any attachment ID as the answer to a file upload question when no new file is uploaded, without checking that the attachment belongs to the submitting user. This makes it possible for authenticated attackers, with Subscriber-level access and above who can take a quiz, to have the URL of any attachment, such as files other students uploaded as quiz answers, shown to them on the quiz page, and to present another user's uploaded file as their own submission to graders.

## References

- https://wpsec.com/vuln/WPSEC-2026-2909/
- https://plugins.svn.wordpress.org/sensei-lms/tags/4.27.0/
- https://wordpress.org/plugins/sensei-lms/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-2909/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.