{"id":"CVE-2026-27807","aliases":["EUVD-2026-9968","GHSA-m9rx-85mx-q9h6"],"status":"published","title":"MarkUs: YAML alias (‘billion laughs’) DoS in config upload","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.","severity":{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00323,"percentile":0.25687,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-776"],"published":"2026-03-06T02:48:28Z","modified":"2026-10-28T02:30:43Z","products":[{"vendor":"markusproject","product":"markus"}],"references":[{"url":"https://github.com/MarkUsProject/Markus/security/advisories/GHSA-m9rx-85mx-q9h6","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory"]},{"url":"https://github.com/MarkUsProject/Markus/releases/tag/v2.9.4","tags":["x_refsource_MISC","Product","Release Notes","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27807.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27807","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-27807","title":"MarkUs: YAML alias (‘billion laughs’) DoS in config upload","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.","status":"published","published":"2026-03-06T02:48:28.384Z","modified":"2026-03-06T16:10:43.887Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-776"],"updated_at":"2026-11-02T14:19:48.826324Z"}],"euvd":[{"id":"EUVD-2026-9968","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.","status":"published","published":"2026-03-06T02:48:28Z","modified":"2026-03-06T16:10:43Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T19:48:07.686491Z"}],"nvd":[{"id":"CVE-2026-27807","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.","status":"published","published":"2026-03-06T04:16:07.81Z","modified":"2026-06-17T10:27:43.023Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"}],"cwes":["CWE-776"],"updated_at":"2026-11-02T14:12:08.279852Z"}],"osv":[{"id":"CVE-2026-27807","title":"MarkUs: YAML alias (‘billion laughs’) DoS in config upload","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.","status":"published","published":"2026-03-06T02:48:28.384Z","modified":"2026-10-28T02:30:43.788449478Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-776"],"updated_at":"2026-11-02T15:45:00.180685Z"}]}}