BinaryMuse toml-node up to 4.1.1 TOML Parser lib/compiler.js toml.parse prototype pollution

Summaryinfo

A vulnerability categorized as critical has been discovered in BinaryMuse toml-node up to 4.1.1. The affected element is the function toml.parse of the file lib/compiler.js of the component TOML Parser. Executing a manipulation can lead to prototype pollution. This vulnerability is tracked as CVE-2026-63376. The attack can be launched remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in BinaryMuse toml-node up to 4.1.1. This vulnerability affects the function toml.parse of the file lib/compiler.js of the component TOML Parser. The manipulation with an unknown input leads to a prototype pollution vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

toml-node is a TOML parser for Node.js and the browser. Prior to 4.1.2, toml.parse() in lib/compiler.js can be tricked by a table path such as a.b.y.__proto__.__proto__, allowing traversal from a scalar value into Number.prototype and Object.prototype. The currentPath tracking value uses both arrays and strings, so valueAssignments records a comma-joined path such as a,b.y while deepRef checks the dot-joined path a.b.y, allowing the duplicate-key guard to miss and attacker-controlled keys to be written to Object.prototype. A table-array prefix-clearing path in addTableArray can also erase guard state before the same __proto__ traversal. Injected properties become visible throughout the Node.js process and can cause denial of service, logic or authorization bypass, or code execution when an application contains a suitable gadget. This issue is fixed in version 4.1.2.

The advisory is available at github.com. This vulnerability was named CVE-2026-63376 since 07/16/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1059 by the MITRE ATT&CK project.

The vulnerability scanner Nessus provides a plugin with the ID 343911 (Linux Distros Unpatched Vulnerability : CVE-2026-63376), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.1.2 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (343911) and EUVD (EUVD-2026-70738). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• BinaryMuse

Name

• toml-node

Version

• 4.1.0
• 4.1.1

Website

• Product: https://github.com/BinaryMuse/toml-node/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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