Description

The MongoDB client library for PHP does not sufficiently sanitize special elements in application-supplied namespace identifiers before using them to construct the target namespace for database operations. An application that incorporates untrusted text into these identifiers may have operations silently directed at a different storage location than the one the application intended.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.1",
  "pubDate": "2026-08-27T20:18:50.913Z",
  "pubdate": "2026-08-27T20:18:50.913Z",
  "executiveSummary": "The MongoDB PHP client library is susceptible to a namespace injection vulnerability arising from insufficient sanitization of application-supplied namespace identifiers.\nThis vulnerability allows an attacker to manipulate the target database or collection for operations, effectively bypassing intended data boundaries.\nThe flaw stems from the library failing to properly process special characters or escape sequences within namespace strings before constructing the final operation path.\nThe primary impact is the unauthorized redirection of database queries and modifications to arbitrary storage locations within the MongoDB instance.\nThis can lead to significant integrity and confidentiality issues, as sensitive operations could be executed against unintended databases or collections.\nAn attacker with the ability to influence input used to construct namespace identifiers can potentially perform unauthorized data exfiltration or corruption.\nNo specific authentication bypass is required; rather, the vulnerability leverages existing application logic to misdirect validly authenticated operations to unintended targets.",
  "technicalDetails": "The root cause of this vulnerability is improper neutralization of special elements within strings used to define namespace identifiers in the MongoDB PHP library.\nIn MongoDB, a namespace consists of the database name and the collection name, joined by a dot (e.g., 'database.collection').\nWhen an application allows untrusted user input to be incorporated into these identifier strings without rigorous validation or escaping, the client library may interpret injected characters as structural separators or command modifiers.\nAttack flow typically begins when a user-controlled parameter—intended only for a collection name—is concatenated into a full namespace identifier.\nBy injecting characters such as the dot operator ('.') or other control characters, an attacker can prematurely terminate the expected namespace or force the library to interpret subsequent strings as a different database or collection path.\nFor example, if an application constructs a namespace using 'db_prefix.' . $user_input, an attacker providing 'other_db.target_coll' would shift the operation from 'db_prefix' to 'other_db', potentially granting unauthorized access to private data stored in that namespace.\nThe vulnerability occurs during the construction phase of the query execution path within the client library, before the request is serialized and transmitted to the MongoDB server.\nBecause the server receives a syntactically valid (though semantically unintended) request, it executes the operation according to the manipulated namespace.\nPost-exploitation, the attacker may achieve unauthorized write access, allowing them to insert, update, or overwrite documents in collections they should not be able to interact with, or read sensitive data by pointing queries to non-public collections.\nThis vulnerability is particularly impactful when the application runs under a privileged MongoDB user account, as the redirection effectively allows the attacker to utilize the application's database permissions to perform actions across the entire cluster."
}