CVE-2026-81527: mongodb c_driver

Vulnerability summary

CVE-2026-81527 is a medium (CVSS 6.9) vulnerability in mongodb c_driver. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 22% of scored vulnerabilities.

Timeline

1. 27-08-2026
   PublishedVulnerability first disclosed.
2. 28-08-2026
   Last modifiedVulnerability information updated.

Description

A NoSQL/expression injection weakness exists in the LINQ-to-aggregation query translation layer of the MongoDB C# Driver, in both aggregation expression and query filter translation. When application-supplied values are embedded in certain query constructs, special elements contained within those values are not properly escaped before the resulting query is transmitted to the database, so portions of the value may be interpreted by the database as query logic rather than as data. A user able to supply values that an application incorporates into an affected query may thereby cause unintended data to be returned or query results to be altered.

• CWE-943Improper Neutralization of Special Elements in Data Query LogicThe 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.