CVE-2026-63376 Vulnerability Analysis & Exploit Details

CVE-2026-63376 Vulnerability Summary

CVE-2026-63376: 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.

CVE-2026-63376 References

External References

• https://github.com/BinaryMuse/toml-node/commit/def6ab5ea99038c0dd482cd6af1745a6af8b4c44
• https://github.com/BinaryMuse/toml-node/commit/dfaff662276adc38a2e03df3139f7119b0185463
• https://github.com/BinaryMuse/toml-node/security/advisories/GHSA-v5mp-jgw5-2x6j
• https://github.com/BinaryMuse/toml-node/security/advisories/GHSA-v5mp-jgw5-2x6j

CWE Common Weakness Enumeration

CAPEC Common Attack Pattern Enumeration and Classification

• Accessing Functionality Not Properly Constrained by ACLs CAPEC-1 In applications, particularly web applications, access to functionality is mitigated by an authorization framework. This framework maps Access Control Lists (ACLs) to elements of the application's functionality; particularly URL's for web apps. In the case that the administrator failed to specify an ACL for a particular element, an attacker may be able to access it with impunity. An attacker with the ability to access functionality not properly constrained by ACLs can obtain sensitive information and possibly compromise the entire application. Such an attacker can access resources that must be available only to users at a higher privilege level, can access management sections of the application, or can run queries for data that they otherwise not supposed to.
• Exploiting Incorrectly Configured Access Control Security Levels CAPEC-180 An attacker exploits a weakness in the configuration of access controls and is able to bypass the intended protection that these measures guard against and thereby obtain unauthorized access to the system or network. Sensitive functionality should always be protected with access controls. However configuring all but the most trivial access control systems can be very complicated and there are many opportunities for mistakes. If an attacker can learn of incorrectly configured access security settings, they may be able to exploit this in an attack.
• Manipulating User-Controlled Variables CAPEC-77 This attack targets user controlled variables (DEBUG=1, PHP Globals, and So Forth). An adversary can override variables leveraging user-supplied, untrusted query variables directly used on the application server without any data sanitization. In extreme cases, the adversary can change variables controlling the business logic of the application. For instance, in languages like PHP, a number of poorly set default configurations may allow the user to override variables.

Other 5 Recently Published CVEs Vulnerabilities

• CVE-2026-90555 – vLLM versions before 0.28.0 fail to validate audio sample rate headers in the transcription endpoint, allowing authenticated clients to bypass dura...
• CVE-2026-90554 – vLLM versions >=0.10.2 and <0.28.0 do not apply any audio decode-size or duration limit when extracting audio from video input for NanoNemotronVL m...
• CVE-2026-90553 – vLLM before 0.28.0 contains a remote code execution vulnerability in the LlavaOnevision2 processor loader that ignores the trust_remote_code parame...
• CVE-2026-90552 – WWBN AVideo through commit c3edcc274c389816d434acadac07ee78eaf330c1 fails to validate playlist ownership in the Playlists_schedules/list.json.php a...
• CVE-2026-90551 – WWBN AVideo through commit c3edcc274c389816d434acadac07ee78eaf330c1 fails to validate playlist ownership in the video_from_program API endpoint, al...