CVE-2026-49293
js-toml vulnerable to CPU exhaustion via O(n^2) BigInt construction on radix-prefixed integer literals
Impact
js-toml is a TOML parser for JavaScript, fully compliant with the TOML 1.0.0 Spec. Versions up to and including 1.1.0 parse hexadecimal / octal / binary integer literals via a hand-written `parseBigInt` loop that multiplies a `BigInt` accumulator by the radix once per input digit. Each iteration performs a `BigInt * BigInt` operation on an accumulator that grows linearly with the number of digits already consumed, so the whole loop is O(n²) in the literal length. The lexer regex places no upper bound on the literal length, so a single TOML document containing one ~500 kB hex literal pins one CPU core for ~40 seconds on a modern laptop (Apple M-series, Node v22). Memory amplification is bounded but CPU amplification is severe and grows quadratically: doubling the literal length quadruples the work. A caller that invokes `load()` on attacker-controlled TOML (configuration upload endpoints, CI/CD systems ingesting third-party `*.toml`, IDE plugins, build tools) is exposed to a single-request CPU exhaustion DoS. Version 1.1.1 fixes the issue.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | js-toml | <= 1.1.0 | 1.1.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Sunnyadn | Js-Toml | before 1.1.1 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-wp3c-266w-4qfq
- https://github.com/sunnyadn/js-toml/security/advisories/GHSA-wp3c-266w-4qfq
- https://nvd.nist.gov/vuln/detail/CVE-2026-49293
- https://github.com/sunnyadn/js-toml/commit/1abcb31dc7b1fa88e4c848a8d108891cfbb96fa2
- https://github.com/sunnyadn/js-toml/releases/tag/v1.1.1