Silent client-side encryption bypass via unescaped field-name regex in CSFLE schema builder

Overview

A client-side encryption schema construction component in the MongoDB C# Driver places caller-supplied field identifiers into a position that is interpreted as a pattern expression, without normalizing or validating them. As a result, an application that designates certain fields for client-side field-level encryption may have the protection silently fail to apply, so data intended to be encrypted is stored and returned in cleartext; conversely, the rule may apply more broadly than intended. No user action is required to cause the condition, and any party with ordinary read access to the stored data — without possession of the encryption keys — can observe the unprotected values.

Affected

• c_driver >= 3.5.0 < 3.13.0

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.