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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

5.3 MediumFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
None
Availability
None

Exploit likelihood

0.20%Unchanged since Oct 13, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.3

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

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.

Record
CVE-2026-109303
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS 3.1
4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness
CWE-639
Updated
2026-11-02
EUVDEUVD-2026-97605 5.3

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.

Record
EUVD-2026-97605
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-pq6r-p5vh-4c89 5.3

Parse Server before 8.6.93 and 9.0.0 before 9.10.1-alpha.13 does not enforce identity-scoped...

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.

Record
GHSA-pq6r-p5vh-4c89
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness
CWE-639
Updated
2026-11-02
NVD 5.3

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.

Record
CVE-2026-109303
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
4.3 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Weakness
CWE-639
Updated
2026-11-02
OSV 5.3

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

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.

Record
CVE-2026-109303
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Weakness
CWE-639
Updated
2026-11-02
OSVBIT-parse-2026-109303 No score

Parse Server before 8.6.93 and 9.0.0 before 9.10.1 protectedFields Bypass via Relation Count Query

Parse Server before 8.6.93 and 9.0.0 before 9.10.1 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.

Record
BIT-parse-2026-109303
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
parse
Bitnami
before 8.6.93, 9.0.0 up to 9.10.1
8.6.939.10.1

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-109303 is a medium vulnerability (CVSS 5.3) in Parse-community Parse-server, published October 12, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.20%, the 10th percentile. Fixed in parse 8.6.93.

References

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