Description
ClassroomIO through 1.0.0 contains an insecure direct object reference vulnerability in the Hono API course submission routes that allows course tutors or admins to modify submissions in other courses. Attackers can supply their own course id with another course's submission UUID to PUT or DELETE handlers to overwrite answers, grades, feedback, and grading status or delete submissions.
References7
- github.com/classroomio/classroomio
- github.com/classroomio/classroomio/blob/v1.0.0/apps/api/src/rou…
- github.com/classroomio/classroomio/blob/v1.0.0/packages/db/src/…
- github.com/classroomio/classroomio/commit/1844ad9671a0d9c2566d3…
- hackmd.io/@hieuPenguinnn/classroomio-course-resource-id-scoping…
- www.vulncheck.com/advisories/classroomio-through-1.0.0-idor-via…
- hackmd.io/@hieuPenguinnn/classroomio-course-resource-id-scoping…
Metrics
- CVSS 3.1
-
6.4
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:L - CVSS 4.0
-
6.1
MEDIUM
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 22 · as of 10 November 2026
- CWE
- CWE-639
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.