Summary
smol-toml: Denial of Service via malformed TOML documents
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
import { parse } from 'smol-toml'
parse('a=[1 #') // never returns; CPU pinned at 100%
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
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.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
Version 1.7.1 properly breaks out of the loop in these situations and throws the expected TomlError.
Frequently Asked Questions
- What is CVE-2026-85730? CVE-2026-85730 is a high-severity security vulnerability in smol-toml (npm), affecting versions <= 1.7.0. It is fixed in 1.7.1.
- Which versions of smol-toml are affected by CVE-2026-85730? smol-toml (npm) versions <= 1.7.0 is affected.
- Is there a fix for CVE-2026-85730? Yes. CVE-2026-85730 is fixed in 1.7.1. Upgrade to this version or later.
- Is CVE-2026-85730 exploitable, and should I be worried? Whether CVE-2026-85730 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-85730 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-85730? Upgrade
smol-tomlto 1.7.1 or later.