VulnerabilityDeferred

CVE-2026-63376

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.

HIGH 8.2EPSS 0.38%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.38%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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 3.1: 8.2 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
EPSS: 0.38% probability · 32th percentile
CISA KEV: Not listed
Weakness: CWE-1321
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.