CVE-2026-27807
MarkUs: YAML alias (‘billion laughs’) DoS in config upload
- State
- Published
- Severity
- 4.9 Medium
- Published
- Mar 6, 2026
- Updated
- Mar 6, 2026
- Reserved
- Feb 24, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 4.9 Medium | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H | GitHub_M |
Weaknesses
- CWE-776 Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
Affected Products
| Product | Versions |
|---|---|
MarkusMarkUsProject |
|
References
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