# CVE-2026-125118: Mongoose: Prototype pollution via Schema.prototype.virtual()


- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 9 Nov 2026
- **Updated:** 9 Nov 2026
- **Also known as:** GHSA-6972-9mcm-vhwj

## What is CVE-2026-125118?

CVE-2026-125118 is a medium-severity vulnerability in Automattic mongoose, published on 9 Nov 2026. 

### Official description

Mongoose is a MongoDB object modeling tool designed to work in an asynchronous environment. Prior to 6.13.12, 7.8.13, 8.24.7, and 9.11.4, Schema.prototype.virtual() builds nested virtual paths without applying the special-property validation already used by Schema.path() and Schema.add(). An attacker who can influence virtual field names in dynamic schemas, content-management form builders, or schema-as-code systems can supply path segments such as __proto__, constructor, or prototype, causing the virtual-path reducer to write enumerable properties to Object.prototype or Function.prototype. The resulting prototype pollution can spoof inherited property checks such as authorization flags and can provide function-prototype gadget state to other server-side JavaScript code. This issue is fixed in versions 6.13.12, 7.8.13, 8.24.7, and 9.11.4.

Weakness: CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes)

## Which versions are affected by CVE-2026-125118?

4 open source packages ship an affected version, including mongoose.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mongoose` | npm | All versions | 6.13.12 |
| `mongoose` | npm | From 7.0.0 | 7.8.13 |
| `mongoose` | npm | From 8.0.0 | 8.24.7 |
| `mongoose` | npm | From 9.0.0 | 9.11.4 |

## How do I fix CVE-2026-125118?

Upgrade mongoose to a fixed version for your release line: 6.13.12, 7.8.13, 8.24.7 or 9.11.4.

## Is CVE-2026-125118 being exploited?

There is no known exploitation of CVE-2026-125118 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-125118 and fix it if it is affected.

What it is: CVE-2026-125118 is a medium-severity vulnerability in Automattic mongoose, published on 9 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-125118 in the wild and no public exploit code.

Affected packages and fixed versions:
- mongoose (npm): affected all versions; fixed in 6.13.12
- mongoose (npm): affected from 7.0.0; fixed in 7.8.13
- mongoose (npm): affected from 8.0.0; fixed in 8.24.7
- mongoose (npm): affected from 9.0.0; fixed in 9.11.4

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-125118/ (Markdown: https://insights.sbomify.com/CVE-2026-125118/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-125118
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-125118
- OSV: https://osv.dev/vulnerability/CVE-2026-125118

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-125118/
Summaries are generated and may contain mistakes; the official description above is the record.