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OpenAdvisories
Medium · 4.9 CVE-2026-27807 EUVD-2026-9968

MarkUs: YAML alias (‘billion laughs’) DoS in config upload

Published Mar 6, 2026 · Updated Mar 6, 2026 · Assigned by GitHub_M

Description

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.

Affected products

VendorProductAffectedFixed
MarkUsProject Markus < 2.9.4 —

References