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CVE

CVE-2026-28405

MarkUs: Stored XSS in Submission HTML Preview Enables Instructor-Context Actions
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CVE

CVE-2026-28405

MarkUs: Stored XSS in Submission HTML Preview Enables Instructor-Context Actions

MarkUs is a web application for the submission and grading of student assignments. Prior to version 2.9.1, the courses/<:courseid>/assignments/<:assignmentid>/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.

Package Versions Affected

Package Version
patch Availability
No items found.

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CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
8
-
3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
C
H
U
-

Related Resources

No items found.

References

https://github.com/MarkUsProject/Markus/releases/tag/v2.9.1, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28405.json, https://github.com/MarkUsProject/Markus/security/advisories/GHSA-p5pc-pxrj-3893, https://nvd.nist.gov/vuln/detail/CVE-2026-28405, https://github.com/MarkUsProject/Markus/commit/55d74f2ddb72d2ec2f29aa2b4cb6b2da10755036

Severity

8

CVSS Score
0
10

Basic Information

Ecosystem
Base CVSS
8
EPSS Probability
0.00044%
EPSS Percentile
0.13571%
Introduced Version
0
Fix Available
55d74f2ddb72d2ec2f29aa2b4cb6b2da10755036

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