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CVE.org (no NVD analysis yet)· CNA GitHub_M

CVE-2026-125116: Mongoose: Discriminator key values matching inherited properties (e.g. __t: 'constructor') bypass schema casting and can poison collections

MediumCVSS 4.8 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 19/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.33% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: mongoose (npm) 7.8.13, 8.24.7, 9.11.4.

Low priority for now. Upgrade to mongoose (npm) 7.8.13, 8.24.7, 9.11.4 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Nov 9, 2026
Updated
Nov 12, 2026
EPSS
0.3% · 27th percentile

Report tools

JSON

Action score

19

Monitor

Low priority for now.

CVSS
19 / 40 · 4.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CNA vs NVD score

NVD
—
CNA · GitHub_M
4.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
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  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • Automattic mongoose

    • < 6.13.12, >= 7.0.0, < 7.8.13, >= 8.0.0, < 8.24.7, >= 9.0.0, < 9.11.4affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
npmmongoosefrom 7.0.0 · before 7.8.137.8.13
npmmongoosefrom 8.0.0 · before 8.24.78.24.7
npmmongoosefrom 9.0.0 · before 9.11.49.11.4
npmmongoosebefore 6.13.126.13.12

Same product

automattic: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-125120Mongoose: sanitizeFilter not applied on countDocuments
    39Monitor
  • CVE-2026-125117Mongoose walks into inherited properties when hydrating, setting, and merging, allowing overwrites of built-in functions (denial of service) and shared schema…
    32Monitor
  • CVE-2026-125119Mongoose: Connection-level sanitizeFilter not applied
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-73562Aug 13, 2026 · Mongoose: Prototype pollution in the update casting via __proto__-prefixed dotted path (Schema._getSchema/path getter)
    26Monitor
  • Later →CVE-2026-125118Nov 9, 2026 · Mongoose: Prototype pollution via Schema.prototype.virtual()
    26Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
npm:mongoose6.13.12Package registry (OSV)
npm:mongoose7.8.13Package registry (OSV)
npm:mongoose8.24.7Package registry (OSV)
npm:mongoose9.11.4Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recorded+1 d
  3. TodayNov 13, 2026+4 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Not on record for this CVE: researcher credit · variant or chain candidate.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
low · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
Low

Weakness class (CWE)

CWE-843 · Access of Resource Using Incompatible Type ('Type Confusion')

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (10 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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