Medium severity · published Oct 12, 2026
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
4.3
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 10% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PA
parse-server · parse-community
9.0.0 before 9.10.1-alpha.13; before 8.6.93 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-109303
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-109303
vendor-advisory
https://github.com/parse-community/parse-server/security/advisories/GHSA-rmhf-xv62-rm99
third-party-advisory
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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