Summary
@eslint/plugin-kit is vulnerable to Regular Expression Denial of Service attacks through ConfigCommentParser
The ConfigCommentParser#parseJSONLikeConfig API is vulnerable to a Regular Expression Denial of Service (ReDoS) attack in its only argument.
Details
The regular expression at packages/plugin-kit/src/config-comment-parser.js:158 is vulnerable to a quadratic runtime attack because the grouped expression is not anchored. This can be solved by prepending the regular expression with [^-a-zA-Z0-9/].
PoC
const { ConfigCommentParser } = require("@eslint/plugin-kit");
const str = `${"A".repeat(1000000)}?: 1 B: 2`;
console.log("start")
var parser = new ConfigCommentParser();
console.log(parser.parseJSONLikeConfig(str));
console.log("end")
// run `npm i @eslint/[email protected]` and `node attack.js`
// then the program will stuck forever with high CPU usage
Impact
This is a Regular Expression Denial of Service attack which may lead to blocking execution and high CPU usage.
A regular expression with worst-case exponential or polynomial matching time is applied to untrusted input, causing excessive CPU use. Typical impact: denial of service when input is crafted to trigger backtracking.
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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Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is GHSA-XFFM-G5W8-QVG7? GHSA-XFFM-G5W8-QVG7 is a low-severity inefficient regular expression (ReDoS) vulnerability in @eslint/plugin-kit (npm), affecting versions < 0.3.4. It is fixed in 0.3.4. A regular expression with worst-case exponential or polynomial matching time is applied to untrusted input, causing excessive CPU use.
- Which versions of @eslint/plugin-kit are affected by GHSA-XFFM-G5W8-QVG7? @eslint/plugin-kit (npm) versions < 0.3.4 is affected.
- Is there a fix for GHSA-XFFM-G5W8-QVG7? Yes. GHSA-XFFM-G5W8-QVG7 is fixed in 0.3.4. Upgrade to this version or later.
- Is GHSA-XFFM-G5W8-QVG7 exploitable, and should I be worried? Whether GHSA-XFFM-G5W8-QVG7 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 GHSA-XFFM-G5W8-QVG7 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 GHSA-XFFM-G5W8-QVG7? Upgrade
@eslint/plugin-kitto 0.3.4 or later.