{"id":"CVE-2026-28405","aliases":["EUVD-2026-9870","GHSA-p5pc-pxrj-3893"],"status":"published","title":"MarkUs: Stored XSS in Submission HTML Preview Enables Instructor-Context Actions","description":"MarkUs is a web application for the submission and grading of student assignments. Prior to version 2.9.1, the courses/\u003c:course_id\u003e/assignments/\u003c:assignment_id\u003e/submissions/html_content route reads the contents of a student-submitted file and renders them without sanitization. This issue has been patched in version 2.9.1.","severity":{"version":"3.1","score":8,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0026,"percentile":0.17883,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-79"],"published":"2026-03-05T20:06:13Z","modified":"2026-10-28T02:31:03Z","products":[{"vendor":"markusproject","product":"markus"}],"references":[{"url":"https://github.com/MarkUsProject/Markus/security/advisories/GHSA-p5pc-pxrj-3893","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory"]},{"url":"https://github.com/MarkUsProject/Markus/commit/55d74f2ddb72d2ec2f29aa2b4cb6b2da10755036","tags":["x_refsource_MISC","Patch","fix"]},{"url":"https://github.com/MarkUsProject/Markus/releases/tag/v2.9.1","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28405.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-28405","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-28405","title":"MarkUs: Stored XSS in Submission HTML Preview Enables Instructor-Context Actions","description":"MarkUs is a web application for the submission and grading of student assignments. Prior to version 2.9.1, the courses/\u003c:course_id\u003e/assignments/\u003c:assignment_id\u003e/submissions/html_content route reads the contents of a student-submitted file and renders them without sanitization. This issue has been patched in version 2.9.1.","status":"published","published":"2026-03-05T20:06:13.433Z","modified":"2026-03-06T17:04:05.19Z","cvss":[{"version":"3.1","score":8,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:20:02.290587Z"}],"euvd":[{"id":"EUVD-2026-9870","description":"MarkUs is a web application for the submission and grading of student assignments. Prior to version 2.9.1, the courses/\u003c:course_id\u003e/assignments/\u003c:assignment_id\u003e/submissions/html_content route reads the contents of a student-submitted file and renders them without sanitization. This issue has been patched in version 2.9.1.","status":"published","published":"2026-03-05T20:06:13Z","modified":"2026-03-06T17:04:05Z","cvss":[{"version":"3.1","score":8,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T19:48:07.686491Z"}],"nvd":[{"id":"CVE-2026-28405","description":"MarkUs is a web application for the submission and grading of student assignments. Prior to version 2.9.1, the courses/\u003c:course_id\u003e/assignments/\u003c:assignment_id\u003e/submissions/html_content route reads the contents of a student-submitted file and renders them without sanitization. This issue has been patched in version 2.9.1.","status":"published","published":"2026-03-05T21:16:21.707Z","modified":"2026-06-17T10:28:33.67Z","cvss":[{"version":"3.1","score":8,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"},{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:07.852448Z"}],"osv":[{"id":"CVE-2026-28405","title":"MarkUs: Stored XSS in Submission HTML Preview Enables Instructor-Context Actions","description":"MarkUs is a web application for the submission and grading of student assignments. Prior to version 2.9.1, the courses/\u003c:course_id\u003e/assignments/\u003c:assignment_id\u003e/submissions/html_content route reads the contents of a student-submitted file and renders them without sanitization. This issue has been patched in version 2.9.1.","status":"published","published":"2026-03-05T20:06:13.433Z","modified":"2026-10-28T02:31:03.01846415Z","cvss":[{"version":"3.1","score":8,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:45:00.180685Z"}]}}