CVE-2026-49293
CPU exhaustion via O(n^2) BigInt construction on radix-prefixed integer literals
Description
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.
INFO
Published Date :
June 19, 2026, 7:16 p.m.
Last Modified :
June 26, 2026, 12:11 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update js-toml to version 1.1.1.
- Avoid parsing untrusted TOML data.
- Monitor CPU usage for TOML parsing.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-49293.
| URL | Resource |
|---|---|
| https://github.com/sunnyadn/js-toml/commit/1abcb31dc7b1fa88e4c848a8d108891cfbb96fa2 | Patch |
| https://github.com/sunnyadn/js-toml/releases/tag/v1.1.1 | Release Notes |
| https://github.com/sunnyadn/js-toml/security/advisories/GHSA-wp3c-266w-4qfq | Exploit Mitigation Vendor Advisory |
| https://github.com/sunnyadn/js-toml/security/advisories/GHSA-wp3c-266w-4qfq | Exploit Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-49293 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-49293
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-49293 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-49293 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 26, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:sunnyadn:js-toml:*:*:*:*:*:node.js:*:* versions up to (excluding) 1.1.1 Added Reference Type GitHub, Inc.: https://github.com/sunnyadn/js-toml/commit/1abcb31dc7b1fa88e4c848a8d108891cfbb96fa2 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/sunnyadn/js-toml/releases/tag/v1.1.1 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/sunnyadn/js-toml/security/advisories/GHSA-wp3c-266w-4qfq Types: Exploit, Mitigation, Vendor Advisory Added Reference Type CISA-ADP: https://github.com/sunnyadn/js-toml/security/advisories/GHSA-wp3c-266w-4qfq Types: Exploit, Mitigation, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 22, 2026
Action Type Old Value New Value Added Reference https://github.com/sunnyadn/js-toml/security/advisories/GHSA-wp3c-266w-4qfq Added SSVC {'id': 'CVE-2026-49293', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-22T14:09:42.727540Z'} -
New CVE Received by [email protected]
Jun. 19, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'sunnyadn', 'product': 'js-toml', 'versions': [{'status': 'affected', 'version': '< 1.1.1'}]}] Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-407 Added CWE CWE-400 Added CWE CWE-1333 Added Reference https://github.com/sunnyadn/js-toml/commit/1abcb31dc7b1fa88e4c848a8d108891cfbb96fa2 Added Reference https://github.com/sunnyadn/js-toml/releases/tag/v1.1.1 Added Reference https://github.com/sunnyadn/js-toml/security/advisories/GHSA-wp3c-266w-4qfq