CVE-2026-109303 parse-community CVE debrief

Who should care

Defenders responsible for Parse Server deployments, particularly those with sensitive data or membership information, should assess exposure and prioritize remediation. This includes reviewing and restricting access to sensitive data and membership information, monitoring for suspicious activity, and implementing additional security measures. Defenders should also verify and upgrade to fixed versions of Parse Server to prevent exploitation.

Why it matters

CVE-2026-109303 is a protectedFields bypass vulnerability in Parse Server via relation count queries. Defenders should prioritize verifying and upgrading to fixed versions to prevent exploitation.

• Authenticated users can bypass protectedFields on count queries, revealing confidential memberships.
• Defenders must verify and upgrade to fixed versions to prevent exploitation.
• Remediation priority is high for deployments with sensitive data or membership information.

Technical summary

Parse Server before 8.6.93 and 9.0.0 before 9.10.1-alpha.13 does not enforce identity-scoped protectedFields on count queries using the $relatedTo operator, exposing the size of protected Relation fields. This allows an authenticated user to bypass protectedFields on count queries, revealing confidential memberships. Defenders should prioritize verifying and upgrading to fixed versions of Parse Server to prevent exploitation. The vulnerability affects Parse Server deployments, particularly those with sensitive data or membership information.

Defensive priority

Defenders should prioritize verifying and upgrading to fixed versions of Parse Server, as the vulnerability allows an authenticated user to bypass protectedFields on count queries.

Recommended defensive actions

• Verify and upgrade to fixed versions of Parse Server (8.6.93 or later, 9.10.1-alpha.13 or later)
• Review and restrict access to sensitive data and membership information
• Monitor for suspicious activity and implement additional security measures
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and source item provide details on the vulnerability, including affected versions and references to vendor advisories. The vulnerability is caused by a lack of enforcement of identity-scoped protectedFields on count queries using the $relatedTo operator. This allows an authenticated user to reveal confidential memberships such as private groups or block lists. Defenders should verify and upgrade to fixed versions to prevent exploitation.

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.