Description

A weakness in the MongoDB C Driver allows special elements in caller-supplied database and collection name components to pass without sanitization when the driver composes the target namespace for an operation. An application that incorporates untrusted input into these name components can have operations directed at a resource other than the one intended.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.4",
  "pubDate": "2026-08-27T20:18:50.773Z",
  "pubdate": "2026-08-27T20:18:50.773Z",
  "executiveSummary": "The MongoDB C Driver contains a critical vulnerability regarding improper input sanitization of database and collection names. This flaw enables an attacker to manipulate the target namespace during operation composition when application logic incorporates untrusted, user-supplied data into these identifiers.\nThis vulnerability is classified as an Injection-type weakness, specifically involving Namespace Injection. By successfully manipulating the namespace, an unauthorized actor can divert database operations—such as reads, writes, or deletions—to unintended resources, potentially leading to unauthorized data access, data corruption, or denial of service.\nThe risk implication is high, as the vulnerability affects the fundamental trust boundary between user-provided input and the driver's internal command routing mechanism. There are no inherent authentication or privilege requirements for this exploit, provided the attacker can influence the input strings processed by the driver. Successful exploitation relies entirely on the application's failure to validate input before passing it to the driver's namespace-generating functions.",
  "technicalDetails": "The root cause of this vulnerability lies in the MongoDB C Driver's failure to sanitize or escape special elements contained within database and collection name strings before they are utilized to compose the final operation namespace. In MongoDB, a namespace is defined by concatenating the database name and the collection name with a dot separator (e.g., 'db.collection').\nThe driver functions responsible for constructing these namespaces trust the input parameters implicitly. If an application developer permits user-supplied input to define these components, an attacker can inject control characters or namespace-altering sequences. By injecting characters such as the dot ('.') delimiter, an attacker can terminate the intended collection name and initiate a reference to an arbitrary collection or even a different database within the MongoDB instance.\nThe exploitation flow begins when a vulnerable application accepts user input (e.g., via HTTP parameters or JSON payloads) and utilizes that input to populate the database or collection arguments in a driver call. For example, if an application expects a collection name like 'user_data', an attacker might supply 'user_data.admin_config'. The driver subsequently composes the namespace as 'target_db.user_data.admin_config'. Depending on the driver's implementation and the underlying MongoDB command protocol, this could result in the operation targeting the 'admin_config' collection instead of the intended 'user_data' collection.\nThis behavior facilitates unauthorized access to sensitive collections that were not intended to be exposed to the user. An attacker could potentially perform unauthorized 'find' operations to exfiltrate data, 'update' operations to modify configuration or credentials, or 'delete' operations to sabotage critical system collections. The attack is restricted to the privileges associated with the database user authenticated by the driver; however, if the driver is running with elevated privileges, the impact of the namespace redirection is amplified accordingly. Because the manipulation occurs at the driver level, the underlying MongoDB server receives what it perceives to be a legitimate command, making traditional server-side access control lists difficult to apply for remediation. The vulnerability exists within the driver's string composition logic, requiring application-level enforcement of strict allow-lists or validation patterns for any identifier-related inputs."
}