Executive brief
The MongoDB C# Driver's GridFS component (a file storage system) contains a vulnerability where file identifiers supplied by applications are improperly processed, allowing attackers to be interpreted as database query operators rather than literal file identifiers. An authenticated attacker could read unintended files, delete all files in a bucket, or rename arbitrary files, compromising data confidentiality and availability.
Technical details
The MongoDB C# Driver's GridFS component fails to properly neutralize special elements in file identifiers used in database queries. The vulnerable code does not enforce exact matching (via $eq operator) when looking up file identifiers, allowing attackers to inject query conditions through crafted identifiers. An authenticated user who can control the file ID parameter passed to affected GridFS operations (delete, read, rename) can cause those operations to match multiple files or all files in a bucket rather than the intended target. This results in unauthorized data access, bulk deletion of files, or unintended file modifications. The fix, implemented in version 3.11.2, wraps all user-supplied file IDs with the $eq operator to ensure literal matching.
Affected products
- MongoDB C# Driver versions prior to 3.11.2
Timeline
- 2026-09-10: disclosed
- 2026-09-09: patched: Fix released in version 3.11.2