Mongoose is a MongoDB object modeling tool designed to work in an asynchronous environment. Prior to 6.13.11, 7.8.12, 8.24.3, and 9.9.2, Mongoose countDocuments() does not apply the configured sanitizeFilter query selector injection defense. An application that enables sanitizeFilter and passes attacker-controlled filter values to countDocuments() can therefore process query operator objects as operators rather than literal values, causing the count to include documents that should not match and potentially undermining authorization or application logic based on that count. This issue is fixed in versions 6.13.11, 7.8.12, 8.24.3, and 9.9.2.

Affected: npm: mongoose

### Impact

`sanitizeFilter` is Mongoose's mechanism for protecting against query selector injection attacks. In older versions of Mongoose, `sanitizeFilter` was not applied for `countDocuments()` queries.

### Patches

Patches have been released for all supported Mongoose major release lines. Please upgrade to the following versions depending on which major version of Mongoose applications are using.

1. `^9.9.2` 2. `^8.24.3` 3. `^7.8.12` 4. `^6.13.11`

### Workarounds

Middleware:

```javascript mongoose.plugin(function() { schema.pre('countDocuments', function() { // This will always apply `sanitizeFilter` on `countDocuments` mongoose.sanitizeFilter(this.getFilter()); }); }); ```