CVE-2026-76073 HumanSignal CVE debrief

Who should care

Defenders responsible for Label Studio instances, especially those with multiple organizations sharing the same instance, should assess exposure and prioritize remediation. They should review the instance's configuration, verify the version, and restrict access to the AnnotationAPI to prevent unauthorized access. Additionally, defenders should monitor for suspicious activity and review compensating controls for exposed systems.

Why it matters

CVE-2026-76073 is a high-severity vulnerability in Label Studio that allows authenticated users to access annotations across organizations. Defenders should prioritize verifying and remediating this vulnerability, especially in environments where multiple organizations share the same Label Studio instance.

• Authenticated users can access annotations from other organizations
• Annotations can be enumerated and accessed across organizations
• Defenders must verify and remediate this vulnerability to prevent unauthorized access

Technical summary

The AnnotationAPI in label_studio/tasks/api.py uses an unscoped queryset, allowing any authenticated user to access annotations across organizations. The view's permission_required entries only check for authentication, not object-level organization permissions. This allows an authenticated user of one organization to enumerate and access annotations belonging to other organizations on the same instance, potentially leading to unauthorized access and data breaches. Defenders should prioritize verifying and remediating this vulnerability, especially in environments where multiple organizations share the same Label Studio instance.

Defensive priority

Defenders should prioritize verifying and remediating this vulnerability, especially in environments where multiple organizations share the same Label Studio instance.

Recommended defensive actions

• Verify the Label Studio instance is updated to a version that scopes annotations to the requesting user's organization
• Restrict access to the AnnotationAPI to only allow authenticated users from the same organization
• Monitor for suspicious activity on the AnnotationAPI endpoint
• 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 vulnerability is caused by the unscoped queryset in AnnotationAPI, which allows any authenticated user to access annotations across organizations. The sibling task endpoint has a constrained queryset, but the annotation detail endpoint does not.

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.