CVE-2026-30835: Parse Server: Malformed `$regex` query leaks database error details in API response
Impact
A malformed $regex query parameter (e.g. [abc) causes the database to return a structured error object that is passed unsanitized through the API response. This leaks database internals such as error messages, error codes, code names, cluster timestamps, and topology details. The vulnerability is exploitable by any client that can send query requests, depending on the deployment's permission configuration.
Patches
The fix sanitizes database error objects so that only a generic "An internal server error occurred" message is returned to clients, while the detailed error is logged server-side. The fix respects the enableSanitizedErrorResponse server option.
Workarounds
There is no workaround other than upgrading. The error leakage occurs in the query execution layer and cannot be mitigated through server configuration or client-side changes.
Resources
- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-9cp7-3q5w-j92g - Fix in Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.0-alpha.6 - Fix in Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.7
Other sources
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.7 and 9.5.0-alpha.6, malformed $regex query parameter (e.g. [abc) causes the database to return a structured error object that is passed unsanitized through the API response. This leaks database internals such as error messages, error codes, code names, cluster timestamps, and topology details. The vulnerability is exploitable by any client that can send query requests, depending on the deployment's permission configuration. This issue has been patched in versions 8.6.7 and 9.5.0-alpha.6.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-30835?
CVE-2026-30835 is considered a moderate severity vulnerability due to potential exposure of sensitive error details.
How do I fix CVE-2026-30835?
To fix CVE-2026-30835, upgrade to Parse Server version 8.6.7 or 9.5.0-alpha.6 or later.
What causes CVE-2026-30835?
CVE-2026-30835 is caused by a malformed `$regex` query parameter that can leak database error details.
Which versions of Parse Server are affected by CVE-2026-30835?
CVE-2026-30835 affects Parse Server versions prior to 8.6.7 and 9.5.0-alpha.6.
Where can I find more information about CVE-2026-30835?
More information about CVE-2026-30835 can be found in the security advisories section on the GitHub repository for Parse Server.