CVE-2026-27807 MEDIUM

CVE-2026-27807: MarkUs: YAML alias (‘billion laughs’) DoS in config upload

Vendor Markusproject
Product Markus
Weakness CWE-776
Published March 6, 2026
Last update March 6, 2026
View on NVD All CVEs

CVSS base score

4.9/10
Attack vector Network
Attack complexity Low
Privileges required High
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

MarkUs is a web application for the submission and grading of student assignments. Prior to version 2.9.4, MarkUs allows course instructors to upload YAML files to create/update various entities (e.g., assignment settings). These YAML files are parsed with aliases enabled. This issue has been patched in version 2.9.4.

Key dates

02Disclosure timeline

March 6, 2026 CVE published
March 6, 2026 Record updated