# CVE-2026-63376

## Summary

- **CVE ID:** CVE-2026-63376
- **Severity:** HIGH
- **CVSS Score:** 8.2 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L)
- **CWE:** CWE-1321
- **Published:** Sep 3, 2026
- **Last Modified:** Sep 5, 2026

## Description

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.

## Affected Products

- BinaryMuse — toml-node (< 4.1.2)

## References

- [CNA](https://github.com/BinaryMuse/toml-node/security/advisories/GHSA-v5mp-jgw5-2x6j)
- [CNA](https://github.com/BinaryMuse/toml-node/commit/def6ab5ea99038c0dd482cd6af1745a6af8b4c44)
- [CNA](https://github.com/BinaryMuse/toml-node/commit/dfaff662276adc38a2e03df3139f7119b0185463)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.38%
- **EPSS Percentile:** 31.6

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._