{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "55d74f2ddb72d2ec2f29aa2b4cb6b2da10755036"
            }
          ],
          "repo": "https://github.com/markusproject/markus",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-p5pc-pxrj-3893"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-79"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28405.json"
  },
  "details": "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.",
  "id": "CVE-2026-28405",
  "modified": "2026-04-01T23:10:17.289142101Z",
  "published": "2026-03-05T20:06:13.433Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/MarkUsProject/Markus/releases/tag/v2.9.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28405.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/MarkUsProject/Markus/security/advisories/GHSA-p5pc-pxrj-3893"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-28405"
    },
    {
      "type": "FIX",
      "url": "https://github.com/MarkUsProject/Markus/commit/55d74f2ddb72d2ec2f29aa2b4cb6b2da10755036"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "MarkUs: Stored XSS in Submission HTML Preview Enables Instructor-Context Actions"
}