---
cve: "CVE-2026-109303"
severity: "MEDIUM"
cvss: 5.3
epss: ""
vendor: "parse-community"
kev: false
exploited: false
published: "2026-10-12 17:17:24"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-10-23T23:25:10+02:00"
---

# CVE-2026-109303

> 5.3 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CNA-Record (Kanon, cvelistV5)

- CNA: **VulnCheck**
- State: PUBLISHED
- Stand: 2026-10-13 16:00:25
- CNA-CVSS: **5.3** (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **no**
  - Technical Impact: **partial**

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |

## Schwachstellen-Klasse

- **CWE-639** — Authorization Bypass Through User-Controlled Key
  The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

## Patch verfügbar (OSV)

- 543a6c852822403812be845a050bfa94e472ba01 (Commit)
- 989531267f47181898bdaa438ff8b48c4d403dd2 (Commit)

## Referenzen

- <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>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-109303/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_