CVE-2026-63376
Prototype pollution in toml-node allows Object.prototype injection (DoS, auth bypass, possible RCE).
Is CVE-2026-63376 being exploited?
Not confirmed. CVE-2026-63376 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.38% probability of exploitation in the next 30 days.
How severe is CVE-2026-63376?
CVE-2026-63376 is rated High with a CVSS score of 8.2. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-63376?
Yes. A fix has been recorded for CVE-2026-63376. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-63376 affect?
CVE-2026-63376 affects toml-node < 4.1.2, Node.js applications using toml-node, Browser apps bundling toml-node. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-63376?
Upgrade to toml-node 4.1.2 immediately; validate/reject untrusted TOML.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker-controlled TOML keys can write to Object.prototype/Number.prototype, enabling prototype pollution leading to DoS, logic/auth bypass, or RCE via gadgets.
Immediate action required
- affected< 4.1.2
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.