CVE-2026-125116Automattic mongoose type confusion
CVE-2026-125116 is a type confusion in Automattic mongoose, rated medium (4.8 on CVSS 3.1).
Why this priority: Medium severity, with no exploitation signal.
Published · Updated · NVD status: Received
What it is
Memory holding one type of object is treated as another, often a route to code execution in browsers and script engines.
How it is reached
An attacker can exploit it over the network, without an account, and nobody has to click anything. Success also depends on conditions the attacker does not fully control.
What an attacker gains
The direct impact is limited: partial access to data or a partial outage. In practice, this kind of flaw lets an attacker crash the process, read memory, or in the worst case run code.
Is it being exploited?
There is no public report of exploitation yet.
What to do
- Upgrade Automattic mongoose to a fixed version for your release line (6.13.12, 7.8.13, 8.24.7).
- Until it is patched, keep it off the internet or behind a VPN, allowlist or authenticating proxy.
Description from NVD
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, Mongoose uses attacker-controlled discriminator key values, including the default __t field, to index plain-object registries such as Model.discriminators and schema.discriminators without requiring an own property. Values such as constructor, toString, or hasOwnProperty can therefore resolve to inherited built-in functions instead of a registered discriminator, causing type confusion in model construction, document creation, hydration, query and update casting, embedded discriminators, and populate operations. In the bulkWrite() insertOne path with skipValidation enabled, a constructor value can cause a raw input object to be stored without schema casting or strict filtering, and a stored poisoned document can make every query that hydrates it fail until the document is removed. The weakness reads inherited properties but does not modify Object.prototype and is not prototype pollution. This issue is fixed in versions 6.13.12, 7.8.13, 8.24.7, and 9.11.4.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Native code: operating systems, browsers and firmware. The flaw sits wherever native code reads untrusted data.
- Network appliances and media or file parsers. The flaw sits wherever native code reads untrusted data.
Trust boundaries in play
- Internet-facing entry points. No account is needed. Any instance reachable from outside your perimeter, through a load balancer, gateway, VPN or exposed admin port, is in scope.
- Wherever native code reads untrusted data. An attacker who crosses it can crash the process, read memory, or in the worst case run code.
Questions to answer about your own systems
- Where does Automattic mongoose run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Read more
Patches and commits
- github.com/Automattic/mongoose/commit/0ecd8040d9b446f36535d79938c130c800f91766
- github.com/Automattic/mongoose/commit/18afab75bea861f625b7c5b54635c84567ec566c
- github.com/Automattic/mongoose/commit/390453c8ce1b36b6cfd1e63432a910da1f3d81d5
- github.com/Automattic/mongoose/commit/8cee51beead554df1f3d05645edb439c69eb2a9b
- github.com/Automattic/mongoose/commit/b26c43554233134ea978c5852babe13be858b2cf
- github.com/Automattic/mongoose/commit/b68f90734b50cd22c89a669c8ca1469d7234b296
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.