Auth bypass in Parse-Community Parse-Server
CVE-2026-109303
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.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/parse-community/parse-server/security/advisories/GHSA-rmhf-xv62-rm99 (vendor-advisory)
- www.vulncheck.com/advisories/parse-server-before-8.6.93-and-9.0.0-before-9.10.1… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-109303?
- CVE-2026-109303 is a medium-severity vulnerability in Parse-Community Parse-Server, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 4.3/10. Published 2026-10-12.
- How severe is CVE-2026-109303?
- Medium severity. CVSS v3 base score is 4.3 out of 10.