CVE-2026-29063
Description
A flaw was found in Immutable.js, a library for persistent immutable data structures. This vulnerability, known as Prototype Pollution, allows an attacker with low privileges to inject unwanted properties into core JavaScript object prototypes without user interaction. By manipulating specific APIs such as mergeDeep(), mergeDeepWith(), merge(), Map.toJS(), and Map.toObject(), a remote attacker could potentially execute arbitrary code or cause a denial of service (DoS).
Statement
Exploitation of this vulnerability requires that an attacker is able to provide arbitrary data to clients of this library in a way that calls the affected functions with data the attacker controls. In most deployments, the ability to provide data in this fashion requires that an attacker has some degree of privileges to access the affected applications.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | 9.8 | 8.8 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | None | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Application Data
An attacker could modify sensitive data or program variables.
Integrity
Technical Impact: Execute Unauthorized Code or Commands
Other,Integrity
Technical Impact: Varies by Context; Alter Execution Logic
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