External risk intelligence

Mongoose countDocuments() Query Selector Injection Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-125120

Mongoose is a software library used within application code to interact with MongoDB databases. While it can be utilized in internet-facing web applications, the library itself is an internal component of a software stack. The reachability depends entirely on how an individual developer implements and exposes the application utilizing the library, rather than the library being an inherently public-facing service.

Halo Surface Signal: 3 out of 5 — possibly public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A security vulnerability has been identified in Mongoose, a tool used for interacting with MongoDB databases. This issue could allow unauthorized modification of document counts, potentially affecting application logic or authorization controls if specific configurations are in place and filters are manipulated by external sources. The main concern is confirming relevance and exposure.

  • Mongoose query counts could be manipulated.
  • Unauthorized data access or logic bypass risks exist.
  • Confirm Mongoose use and filter input controls.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability if an application uses a specific Mongoose function, `countDocuments()`, with a feature called `sanitizeFilter` enabled. By providing specially crafted input to this function, an attacker could manipulate how the database query is processed. This manipulation could lead to incorrect document counts, potentially bypassing security checks or altering application behavior.

  • No special access required to trigger.
  • Manipulating database query filters.
  • Incorrect counts undermine application logic.

Live Threat

Current exploitation, exposure, and threat context

When applications using Mongoose enable `sanitizeFilter` and pass attacker-controlled input to `countDocuments()`, query operators may be processed as literal values. This could lead to inaccurate document counts that undermine application logic or authorization when the count is relied upon.

  • Application document counts may be inaccurate.
  • Attacker-controlled input could alter query processing.
  • Authorization or application logic may be undermined.

Operational Fix

Recommended remediation, mitigation, and detection steps

Technical leaders and system owners should first identify applications using Mongoose and confirm their reachability and business criticality to prioritize remediation. The first practical step is to locate all instances of Mongoose within your environment, verify exposure, and identify the accountable application or platform owner. Subsequently, a risk-based remediation plan should be developed, potentially involving vendor coordination or temporary mitigations if immediate patching is not feasible.

  • Application owners must address this.
  • Verify direct exposure and business criticality.
  • Plan coordinated updates or mitigations.

Supplementary metadata

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

Frequently asked questions

What is Mongoose and why is it used?

Mongoose is a popular Node.js library that provides an object modeling layer for MongoDB. Developers use it to define schemas and manage interactions between their application code and the database. It acts as a bridge, allowing software to query, save, and manipulate data structures within MongoDB using a consistent, structured interface rather than writing raw database commands.

How does CVE-2026-125120 impact query logic?

This vulnerability involves Improper Neutralization of Special Elements used in an OS Command, known as a Query Selector Injection. It happens when the `countDocuments()` function fails to apply the intended `sanitizeFilter` protection. Consequently, the database interprets attacker-provided input as active query operators instead of simple text, allowing them to change the criteria of a count operation and potentially bypass authorization logic.

When does this vulnerability trigger?

The issue triggers when an application explicitly enables the `sanitizeFilter` feature and subsequently passes untrusted user input directly into the `countDocuments()` function. It does not trigger if the application does not use this specific sanitization configuration, nor does it affect code paths that do not accept external input for document filtering.

Is my application at risk according to Halo Surface Signal?

Halo Surface Signal notes that because Mongoose is a library embedded within your application code, its reachability depends on how you built your service. While it can be used in internet-facing web applications, the vulnerability is not a public-facing service itself. You should evaluate whether your application processes untrusted user input within the `countDocuments()` function.

How do I remediate this Mongoose vulnerability?

Start by identifying all applications in your environment that utilize the Mongoose library. Once identified, verify if those applications rely on the `countDocuments()` function with `sanitizeFilter` enabled. The primary fix is to update your Mongoose installation to the patched versions—6.13.11, 7.8.12, 8.24.3, or 9.9.2—as these releases correctly apply the expected security filters to prevent query injection.

References