CVE-2026-124551 Details
Description
ClassroomIO through 1.0.0 contains an authorization bypass vulnerability that allows authenticated users of any organization to clone other tenants' courses via the POST /course/:courseId/clone endpoint. Attackers who know a target course id can copy its sections, lessons, exercises, and quiz answer keys into their own organization, exposing private course content.
A vulnerability exists in ClassroomIO versions through 1.0.0, allowing authenticated users to bypass authorization when cloning courses from other organizations. The issue arises in the Hono backend API, specifically within the course cloning route. The vulnerability enables users to copy private course content, including sections, lessons, exercises, and quiz answer keys, from one organization to another, thereby exposing sensitive material.
Users should update to the latest version of ClassroomIO, where this vulnerability has been fixed. Instructions for updating can be found in the ClassroomIO documentation.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Nov 8, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/classroomio/classroomio | [email protected] | Source CodeVendor |
| https://github.com/classroomio/classroomio/blob/v1.0.0/apps/api/src/routes/course/course.ts#L584-L612 | [email protected] | Source CodeVendor |
| https://github.com/classroomio/classroomio/blob/v1.0.0/apps/api/src/services/course/clone.ts#L202-L290 | [email protected] | Source CodeVendor |
| https://github.com/classroomio/classroomio/commit/6630b73f8d53e316de6f575a170b093da6bf3cca | [email protected] | Source CodeVendor |
| https://github.com/classroomio/classroomio/issues/1414 | [email protected] | ExploitIssue TrackingTechnical DescriptionVendor |
| https://hackmd.io/@hieuPenguinnn/classroomio-course-clone-cross-org-content-exfiltration | [email protected] | ExploitTechnical Analysis |
| https://www.vulncheck.com/advisories/classroomio-through-1.0.0-cross-organization-course-disclosure-via-clone-endpoint | [email protected] | AdvisoryBundle |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-639 | Authorization Bypass Through User-Controlled Key | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| ClassroomIO | <= 1.0.0 (semver) |
CPE
Remediation
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Change History
1 change record found show changes
| Date | Action | Recorded By |
|---|---|---|
| Nov 8, 2026 | New CVE Received | [email protected] |