What’s Vulnerable › Vulnerabilities

CVE-2026-109303: Parse Server before 8.6.93 and 9.0.0 before 9.10.1-alpha.13 protectedFields Bypass via Relation Count Query

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-12 · updated 2026-10-13
• Weakness: CWE-639

Description

Parse Server before 8.6.93 and 9.0.0 before 9.10.1-alpha.13 does not enforce identity-scoped protectedFields (authenticated, role, or per-user groups) on count queries using the $relatedTo operator, exposing the size of protected Relation fields. An authenticated user who can read the owning object can combine counts with an objectId constraint as a membership oracle to reveal confidential memberships such as private groups or block lists.

Affected products

• parse-community parse-server: from 9.0.0 before 9.10.1-alpha.13; before 8.6.93 — fixed in 8.6.93, 9.10.1-alpha.13

How to fix

Upgrade to a fixed version: parse-community parse-server 8.6.93, 9.10.1-alpha.13. Check the vendor advisory for mitigations.

References

• https://github.com/parse-community/parse-server/security/advisories/GHSA-rmhf-xv62-rm99
• https://www.vulncheck.com/advisories/parse-server-before-8.6.93-and-9.0.0-before-9.10.1-alpha.13-protectedfields-bypass-via-relation-count-query

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