Parse Server's Cloud Hooks and Cloud Jobs bypass `readOnlyMasterKey` write restriction
Date: 2026-03
Affected: npm/parse-server, npm/parse-server
Attack vector: data-exfiltration
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2026-29182
CWE: CWE-863

### Impact Parse Server's `readOnlyMasterKey` option allows access with master-level read privileges but is documented to deny all write operations. However, some endpoints incorrectly accept the `readOnlyMasterKey` for mutating operations. This allows a caller who only holds the `readOnlyMasterKey` to create, modify, and delete Cloud Hooks and to start Cloud Jobs, which can be used for data exfiltration. Any Parse Server deployment that uses the `readOnlyMasterKey` option is affected. Note than an attacker needs to know the `readOnlyMasterKey` to exploit this vulnerability. ### Patches The fix adds authorization checks, rejecting mutating requests made with the `readOnlyMasterKey`. ### Workarounds There is no known workaround other than upgrading. If upgrading is not immediately possible, ensure the `readOnlyMasterKey` value is not shared with untrusted parties. ### Resources - GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-vc89-5g3r-cmhh - Fixed in Parse Server 9.4.1-alpha.3: https://github.com/parse-community/parse-server/releases/tag/9.4.1-alpha.3 - Fixed in Parse Server 8.6.4: https://github.com/parse-community/parse-server/releases/tag/8.6.4


Mitigations:

Architectural layers (MAESTRO):