Vulnerability · Published Oct 22, 2026 · Assigned by mongodb
CVE-2026-114653Silent client-side encryption bypass via unescaped field-name regex in CSFLE schema builder
Medium 6.5
In plain English
A medium-severity security flaw in C# Driver from MongoDB. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities).
Official description
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 products (as reported)
Weakness: CWE-185 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N