CVE-2026-49293 PUBLISHED

CPU exhaustion via O(n^2) BigInt construction on radix-prefixed integer literals

Assigner: GitHub_M
Reserved: 28.05.2026 Published: 19.06.2026 Updated: 19.06.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 7.5

Product Status

Vendor sunnyadn
Product js-toml
Versions
  • Version < 1.1.1 is affected

References

Problem Types

  • CWE-400: Uncontrolled Resource Consumption CWE
  • CWE-407: Inefficient Algorithmic Complexity CWE
  • CWE-1333: Inefficient Regular Expression Complexity CWE