CVE-2024-21539Public exploitNetwork attack vector

Process hang via runaway whitespace matching

Published Nov 19, 2024 · Updated Aug 18, 2026

Regular expression denial of service in ESLint @eslint/plugin-kit before 0.2.3 allows attackers to hang a process via a crafted string. The ConfigCommentParser.parseStringConfig method applies a greedy whitespace expression before separators, repeatedly rescanning long whitespace runs that end in a nonseparator. Reachability requires a consuming application to pass attacker-controlled configuration-comment text into this parser; CPU exhaustion then hangs or crashes that process.

CVSS severity3.5
Low
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Regular expression denial of service in ESLint @eslint/plugin-kit before 0.2.3 allows attackers to hang a process via a crafted string. The ConfigCommentParser.parseStringConfig method applies a greedy whitespace expression before separators, repeatedly rescanning long whitespace runs that end in a nonseparator. Reachability requires a consuming application to pass attacker-controlled configuration-comment text into this parser; CPU exhaustion then hangs or crashes that process.

The record

CVE
CVE-2024-21539
Published
Nov 19, 2024
Updated
Aug 18, 2026
Vendor
ESLint
Product
@eslint/plugin-kit
Classifications
CWE-770, CWE-1333, CAPEC-492, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 19, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <0.2.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ESLint · @eslint/plugin-kitversion=0 <0.2.3
ESLint · Rewriteversion=0 <0.2.3

Published CVSS scores

3.5GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
CWE-1333Inefficient Regular Expression Complexity
CAPEC-492Regular Expression Exponential Blowup
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo