GitHub Advisoryadvisory · npm
GHSA-7w5x-hrqm-74c2 smol-toml: Denial of Service via malformed TOML documents
HIGH
Official page ↗
- Aliases
- CVE-2026-85730
- Ecosystem
- npm
- Packages
- smol-toml
- Severity
- High
- CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Weaknesses
- CWE-606, CWE-835
- Reviewed
- 2026-09-09
Affected packages
• npm smol-toml: < 1.7.1 → fixed in 1.7.1
Description
Summary
`parse()` can be forced into an infinite loop when a value inside an array or inline table is followed by a comment that has no trailing newline (i.e. the comment "ends" the document).
The library fails to exit an internal loop when attempting to find the end of the structure, resetting its cursor to the beginning of the string instead. This causes the parser to indefinitely hang, compromising the availability of the service.
Proof of concept
```js
import { parse } from 'smol-toml'
parse('a=1 #') // never returns; CPU pinned at 100%
```
Impact
Applications which parse arbitrary TOML documents can suffer major availability issues if they receive malicious input. This issue is particularly severe for these use-cases, and it is strongly advised to upgrade to an up-to-date version of the library as soon as possible.
If your use-case does not involve parsing arbitrary TOML documents from untrusted sources, the impact is much lower in practice, although it's still advisable to update to version 1.7.1.
Patches
Version 1.7.1 properly breaks out of the loop in these situations and throws the expected `TomlError`.
Workarounds
None that don't involve refactors. Update the library as soon as possible if your use-case involves parsing arbitrary TOML documents from untrusted sources.
Reported By : [Ravindu Lakmina Munaweera
Related
Alias · CVE (1)
- CVE-2026-85730 smol-toml is a small, fast, and correct TOML parser and serializer. vulnerability
References
- https://github.com/squirrelchat/smol-toml/security/advisories/GHSA-7w5x-hrqm-74c2 web
- https://nvd.nist.gov/vuln/detail/CVE-2026-85730 advisory
- https://github.com/squirrelchat/smol-toml/commit/30f5c367d946b695f379b5d4f0946b2f0a0a8c2f web
- https://github.com/squirrelchat/smol-toml package
- https://github.com/squirrelchat/smol-toml/releases/tag/v1.7.1 web
- https://medium.com/@ravindu.lakmina1/seven-bytes-that-freeze-a-node-js-server-forever-the-story-of-cve-2026-85730-3213328b38f0 web