Parse Server is an open source backend server. In versions prior to 8.6.90 and in versions from 9.0.0 prior to 9.10.1-alpha.9, the device token deduplication logic for installation records does not validate the type of client-supplied installation fields before using them to build database queries. An unauthenticated remote attacker who knows only the public application ID can submit non-string values in these fields to inject query operators, causing the deduplication cleanup — which runs with elevated privileges before class-level permissions are evaluated — to delete every device registration in the application or an attacker-chosen subset of them. No account, session token, master key, or user interaction is required. Deleted registrations cannot be recovered on the server, so push notifications cannot be delivered until every client re-registers. Any deployment that exposes the REST API to clients and uses push notifications is affected in its default configuration. Versions 8.6.90 and 9.10.1-alpha.9 fix the issue by rejecting non-string values with a client error and by scoping the deduplication cleanup to the calling application. No workaround other than upgrading is available.
Weakness
The product generates a query intended to access or manipulate data in a data store such as a database, but it does not neutralize or incorrectly neutralizes special elements that can modify the intended logic of the query.
Extended Description
Depending on the capabilities of the query language, an attacker could inject additional logic into the query to:
The ability to execute additional commands or change which entities are returned has obvious risks. But when the product logic depends on the order or number of entities, this can also lead to vulnerabilities. For example, if the query expects to return only one entity that specifies an administrative user, but an attacker can change which entities are returned, this could cause the logic to return information for a regular user and incorrectly assume that the user has administrative privileges. While this weakness is most commonly associated with SQL injection, there are many other query languages that are also subject to injection attacks, including HTSQL, LDAP, DQL, XQuery, Xpath, and “NoSQL” languages.