CVE-2026-111368 classroomio CVE debrief

Who should care

Defenders responsible for ClassroomIO instances, especially those exposed to untrusted users, should assess their exposure and prioritize remediation. They should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance. Defenders need to verify and remediate this vulnerability to prevent potential data tampering or unauthorized access.

Why it matters

ClassroomIO through 1.0.0 contains an insecure direct object reference vulnerability that allows course tutors or admins to modify submissions in other courses, potentially leading to data tampering or unauthorized access. Defenders should prioritize verifying and remediating this vulnerability in their inventory of ClassroomIO instances, especially those exposed to untrusted users.

• Course tutors or admins may be able to modify submissions in other courses, potentially leading to data tampering or unauthorized access.
• Defenders need to verify and remediate this vulnerability to prevent potential data tampering or unauthorized access.
• Remediation priority is high for exposed instances, as exploitation could lead to data tampering or unauthorized access.

Technical summary

The vulnerability exists in the Hono API course submission routes of ClassroomIO through 1.0.0. It allows course tutors or admins to modify submissions in other courses by supplying their own course ID with another course's submission UUID. This could lead to unauthorized access or data tampering. The vulnerability is caused by insufficient validation of user input in the course submission routes. Defenders should prioritize verifying and remediating this vulnerability in their inventory of ClassroomIO instances, especially those exposed to untrusted users.

Defensive priority

Defenders should prioritize verifying and remediating this vulnerability in their inventory of ClassroomIO instances, especially those exposed to untrusted users.

Recommended defensive actions

• Verify inventory of ClassroomIO instances and check for exposure to untrusted users
• Remediate vulnerable instances by updating to a patched version
• Monitor for suspicious activity on course submission routes
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the insecure direct object reference vulnerability in ClassroomIO through 1.0.0. The vulnerability allows course tutors or admins to modify submissions in other courses by supplying their own course ID with another course's submission UUID.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.