mongo-object up to 3.0.2 util util.js expandKey prototype pollution

CVSS Meta Temp Score
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CTI Interest Score
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7.0$0-$5k2.67

Summaryinfo

A vulnerability marked as critical has been reported in mongo-object up to 3.0.2. This affects the function expandKey of the file util.js of the component util. Performing a manipulation results in prototype pollution. This vulnerability is identified as CVE-2026-16266. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as critical, was found in mongo-object up to 3.0.2. This affects the function expandKey of the file util.js of the component util. The manipulation with an unknown input leads to a prototype pollution vulnerability. CWE is classifying the issue as CWE-1321. 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. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Versions of the package mongo-object before 3.0.3 are vulnerable to Prototype Pollution via the expandKey() function in util.js. An attacker can modify the JavaScript prototype chain by supplying a crafted property path containing special keys such as __proto__.

It is possible to read the advisory at security.snyk.io. This vulnerability is uniquely identified as CVE-2026-16266 since 07/20/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059 according to MITRE ATT&CK.

Upgrading to version 3.0.3 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-46151). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Prototype pollution
CWE: CWE-1321 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: mongo-object 3.0.3

Timelineinfo

07/20/2026 CVE reserved
07/21/2026 +1 days Advisory disclosed
07/21/2026 +0 days VulDB entry created
07/21/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: security.snyk.io
Status: Confirmed

CVE: CVE-2026-16266 (🔒)
GCVE (CVE): GCVE-0-2026-16266
GCVE (VulDB): GCVE-100-380811
EUVD: 🔒

Entryinfo

Created: 07/21/2026 07:50
Updated: 07/21/2026 10:43
Changes: 07/21/2026 07:50 (54), 07/21/2026 10:43 (1)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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