VulnerabilityPublished 10 Nov 2026

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

Affects mongooseSource GCVE Database

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Authoritative record:CVE-2026-125118· Medium 6.5

Not known to be exploited · CVSS 6.5 Medium : upgrade to 6.13.12 when convenient.

Data as of 10 Nov 2026, 21:07 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	6.5

Patch: Available – fixed in 6.13.12, 7.8.13, 8.24.7 +1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
npmmongoose	Affected <6.13.12	Fixed in 6.13.12
npmmongoose	Affected >=7.0.0 <7.8.13	Fixed in 7.8.13
npmmongoose	Affected >=8.0.0 <8.24.7	Fixed in 8.24.7
npmmongoose	Affected >=9.0.0 <9.11.4	Fixed in 9.11.4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and has been released in Mongoose versions 6.13.12, 7.8.13, 8.24.7, and 9.11.4. Users should upgrade to these or later versions to remediate the vulnerability. No alternative mitigations are specified. Since this is a prototype pollution vulnerability exploitable via attacker-controlled schema field names, avoiding untrusted input in schema definitions is recommended until patched.

Description

Mongoose versions prior to 6.13.12, 7.0.0 to before 7.8.13, 8.0.0 to before 8.24.7, and 9.0.0 to before 9.11.4 contain a prototype pollution vulnerability via the Schema.prototype.virtual() method. This vulnerability allows attacker-controlled schema field names to modify Object.prototype and Function.prototype, potentially affecting all objects and functions in the environment. The issue persists because the 2022 fix for similar vulnerabilities did not cover the virtual() method. A patch is available in versions 6.13.12, 7.8.13, 8.24.7, and 9.11.4.

Impact

An attacker able to influence schema field names in dynamic schemas or schema-as-code scenarios can exploit this vulnerability to pollute Object.prototype and Function.prototype. This pollution adds enumerable properties visible on all objects and functions, which can spoof property existence checks (e.g., ({ }).isAdmin) and may be leveraged as a gadget primitive in server-side JavaScript attacks. The impact includes integrity loss and potential denial of service (as indicated by the CVSS vector). There is no indication of confidentiality impact. No known exploits in the wild have been reported.

Summary

The vulnerability in Mongoose arises from the Schema.prototype.virtual() method, which constructs virtual paths without the specialProperties check that was added to Schema.path() and Schema.add() in previous fixes (CVE-2022-2564 / CVE-2022-24304). This omission allows an attacker to supply schema field names containing prototype pollution vectors such as '__proto__', 'constructor', or 'prototype'. These names cause assignments to Object.prototype or Function.prototype, leading to pollution of these global prototypes. The pollution results in enumerable keys added to Object.prototype and Function.prototype, which can spoof property checks on all objects and functions, potentially enabling privilege escalation or other logic bypasses in server-side JavaScript environments. Proof-of-concept code demonstrates how virtual paths with these special names lead to prototype pollution. The vulnerability affects multiple maintained release lines of Mongoose and has a CVSS 3.1 base score of 6.5 (medium severity).

CWE-1321Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution) (opens in a new tab)
Variant weakness
The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
Implementation
By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
Architecture and Design
By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
Implementation · Input Validation
When handling untrusted objects, validating using a schema can be used.
OWASP Cheat Sheets
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V5.1.2 (opens in a new tab)
Attack patterns
Accessing Functionality Not Properly Constrained by ACLs (opens in a new tab)
Exploiting Incorrectly Configured Access Control Security Levels (opens in a new tab)
Manipulating User-Controlled Variables (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Nov 2026, 21:07 UTC

WeaknessesCWE-1321

Technical details

References

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