{"id":"CVE-2026-27807","summary":"MarkUs: YAML alias (‘billion laughs’) DoS in config upload","details":"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.","aliases":["GHSA-m9rx-85mx-q9h6"],"modified":"2026-04-10T05:37:23.003528Z","published":"2026-03-06T02:48:28.384Z","database_specific":{"cna_assigner":"GitHub_M","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27807.json","cwe_ids":["CWE-776"]},"references":[{"type":"WEB","url":"https://github.com/MarkUsProject/Markus/releases/tag/v2.9.4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27807.json"},{"type":"ADVISORY","url":"https://github.com/MarkUsProject/Markus/security/advisories/GHSA-m9rx-85mx-q9h6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27807"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/markusproject/markus","events":[{"introduced":"0"},{"fixed":"2aa90f8a047c2484147de12c464d08d4be964029"}]}],"versions":["0.10.0","1.8.0-rc1","v1.10.0","v1.10.0-rc","v1.10.1","v1.10.1-rc","v1.10.2","v1.10.3","v1.10.4","v1.11.0","v1.11.1","v1.11.2","v1.11.3","v1.11.4","v1.11.5","v1.12.0","v1.12.1","v1.12.2","v1.12.3","v1.12.4","v1.12.5","v1.13.0","v1.13.1","v1.13.2","v1.13.3","v1.14.0","v1.8.0","v1.8.0-rc2","v1.8.1","v1.8.2","v1.8.3","v1.8.4","v1.9.0","v1.9.1","v1.9.2","v1.9.3","v2.0.0","v2.0.1","v2.0.10","v2.0.2","v2.0.3","v2.0.4","v2.0.5","v2.0.6","v2.0.7","v2.0.8","v2.0.9","v2.1.0","v2.1.1","v2.1.2","v2.1.3","v2.1.4","v2.1.5","v2.1.6","v2.1.7","v2.2.0","v2.2.1","v2.2.2","v2.2.3","v2.2.4","v2.3.0","v2.3.1","v2.3.2","v2.3.3","v2.3.4","v2.4.0","v2.4.1","v2.4.10","v2.4.11","v2.4.12","v2.4.2","v2.4.3","v2.4.4","v2.4.5","v2.4.6","v2.4.7","v2.4.8","v2.4.9","v2.5.0","v2.5.1","v2.5.2","v2.5.3","v2.6.0","v2.6.1","v2.7.0","v2.7.1","v2.8.0","v2.8.1","v2.8.2","v2.9.0","v2.9.1","v2.9.2","v2.9.3"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27807.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H"}]}