CVE-2026-16266
mongo-object Prototype Pollution Vulnerability
Description
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__.
INFO
Published Date :
July 21, 2026, 6:16 a.m.
Last Modified :
July 21, 2026, 6:16 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-16266
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update the mongo-object package to version 3.0.3 or newer.
- Avoid using the expandKey() function with untrusted input.
- Sanitize user-supplied property paths before using them.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-16266.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-16266 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-16266
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-16266 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-16266 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jul. 21, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'n/a', 'product': 'mongo-object', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.0.3', 'versionType': 'semver'}]}] Added Description 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__. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N Added CWE CWE-1321 Added Reference https://github.com/longshotlabs/mongo-object/blob/4f7a570f2a2fcfa9417b7870d5f859e9574ec73c/src/util.ts%23L251 Added Reference https://github.com/longshotlabs/mongo-object/commit/638314107d8b397e5453c28e41729522b3e8d67c Added Reference https://github.com/longshotlabs/mongo-object/issues/27 Added Reference https://security.snyk.io/vuln/SNYK-JS-MONGOOBJECT-13816714