Home/CVE/MarkUs is a web application for the submission and grading of student assignments. Prior to version 2.9.1, the courses/<
CVE

CVE-2026-28405

MarkUs is a web application for the submission and grading of student assignments. Prior to version 2.9.1, the courses/<

MarkUs is a web application for the submission and grading of student assignments. Prior to version 2.9.1, the courses/<:course_id>/assignments/<:assignment_id>/submissions/html_content route reads the contents of a student-submitted file and renders them without sanitization. This issue has been patched in version 2.9.1.

HIGH · CVSS 8 EPSS 0.00044
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
▤

Affected Products & Versions

1
markusproject markus< 2.9.1
▣

Scoring & Timeline

8
HIGH · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD05 Mar 2026 · 09:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/MarkUsProject/Markus/commit/55d74f2ddb72d2ec2f29aa2b4cb6b2da10755036Patch
https://github.com/MarkUsProject/Markus/releases/tag/v2.9.1Release Notes
https://github.com/MarkUsProject/Markus/security/advisories/GHSA-p5pc-pxrj-3893Vendor Advisory
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