CVE-2026-33228
Description
A flaw was found in flatted, a JavaScript Object Notation (JSON) parser designed for handling circular data structures. A remote attacker can exploit this vulnerability by providing specially crafted JSON input. The parse() function in flatted fails to properly validate string values used as array index keys, allowing an attacker to manipulate internal JavaScript object prototypes. This prototype pollution can enable an attacker to execute arbitrary code or cause a denial of service, impacting the availability and integrity of affected systems.
Statement
A Critical vulnerability was discovered in 'flatted', a JavaScript JSON parser. It could enable a remote, unauthenticated attacker to execute arbitrary code or cause a denial of service. Exploitation involves prototype pollution by providing a specially crafted JSON input. Red Hat products that process un-trusted JSON data and utilize the 'flatted' library are at risk if they do not properly sanitize input.
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 | 9.8 | 9.8 | 9.8 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| 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:N/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:N/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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