Vulnerability 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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/BinaryMuse/toml-node/commit/def6ab5ea99038c0dd482cd6af1745a6a
- https://github.com/BinaryMuse/toml-node/commit/dfaff662276adc38a2e03df3139f7119b
- https://github.com/BinaryMuse/toml-node/security/advisories/GHSA-v5mp-jgw5-2x6j
- https://github.com/BinaryMuse/toml-node/security/advisories/GHSA-v5mp-jgw5-2x6j
FAQ
What is CVE-2026-63376?
CVE-2026-63376 is a vulnerability with a CVSS score of 8.2 (HIGH). 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 scal...
How severe is CVE-2026-63376?
CVE-2026-63376 has been rated HIGH with a CVSS base score of 8.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-63376?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.