CVE-2024-4068 Overview
CVE-2024-4068 is a Memory Exhaustion vulnerability in the NPM package braces, versions prior to 3.0.3. The vulnerability exists because the package fails to limit the number of characters it can handle during parsing. When a malicious user sends "imbalanced braces" as input, the parsing logic in lib/parse.js enters an infinite loop, causing the program to continuously allocate heap memory without releasing it. This ultimately leads to JavaScript heap exhaustion and application crash.
The braces package is widely used in the Node.js ecosystem for brace expansion, making this vulnerability potentially impactful across numerous dependent packages and applications.
Critical Impact
Attackers can remotely cause denial of service by sending specially crafted input with imbalanced braces, leading to memory exhaustion and application crashes.
Affected Products
- jonschlinkert braces versions prior to 3.0.3
- Node.js applications using vulnerable braces package
- Dependent packages in the micromatch ecosystem
Discovery Timeline
- May 14, 2024 - CVE-2024-4068 published to NVD
- December 31, 2025 - Last updated in NVD database
Technical Details for CVE-2024-4068
Vulnerability Analysis
The vulnerability resides in the parsing logic of the braces package, specifically within lib/parse.js. When processing input strings containing imbalanced braces, the parser enters a loop that continuously allocates memory on the JavaScript heap. The lack of proper input validation and resource limits allows an attacker to exploit this behavior by crafting malicious input strings.
The original implementation defined MAX_LENGTH as 1024 * 64 (65,536 characters) and included a MAX_SYMBOLS constant of 1024, but these safeguards were insufficient to prevent the memory exhaustion condition when processing imbalanced brace patterns. The parsing function would continue iterating without proper termination conditions, allocating new objects and strings without garbage collection until the V8 heap limit was reached.
Root Cause
The root cause is improper input validation (CWE-400: Uncontrolled Resource Consumption) combined with inadequate loop termination conditions (CWE-1050: Excessive Platform Resource Consumption within a Loop). The lib/parse.js module lacks proper validation to detect and reject malformed input containing imbalanced braces before entering the parsing loop, and once in the loop, there are no safeguards to prevent unbounded memory allocation.
Attack Vector
This vulnerability is exploitable over the network without requiring authentication or user interaction. An attacker can send specially crafted input containing imbalanced braces to any application that processes user-supplied data through the braces package. The attack requires no special privileges and can be executed remotely against any exposed endpoint that utilizes brace expansion functionality.
The security patch modified lib/constants.js to reduce MAX_LENGTH from 65,536 to 10,000 characters and removed the unused MAX_SYMBOLS constant:
'use strict';
module.exports = {
- MAX_LENGTH: 1024 * 64,
- MAX_SYMBOLS: 1024,
+ MAX_LENGTH: 10000,
// Digits
CHAR_0: '0', /* 0 */
Source: GitHub Commit Reference
The corresponding changes in lib/parse.js removed the dependency on validation utilities:
'use strict';
const stringify = require('./stringify');
-const {isCorrectBraces, validateInput} = require('./validate-input');
/**
* Constants
*/
const {
MAX_LENGTH,
- MAX_SYMBOLS,
CHAR_BACKSLASH, /* \ */
CHAR_BACKTICK, /* ` */
CHAR_COMMA, /* , */
Source: GitHub Commit Reference
Detection Methods for CVE-2024-4068
Indicators of Compromise
- Sudden memory spikes in Node.js processes handling user input
- Application crashes with JavaScript heap out of memory errors
- Unusual patterns in request payloads containing excessive or imbalanced brace characters
- High memory consumption in services using brace expansion functionality
Detection Strategies
- Implement application performance monitoring (APM) to detect abnormal memory allocation patterns in Node.js applications
- Review dependency trees using npm audit or yarn audit to identify vulnerable versions of the braces package
- Monitor process-level resource utilization for Node.js services to detect memory exhaustion attempts
- Analyze incoming request payloads for patterns of imbalanced braces or excessive special characters
Monitoring Recommendations
- Configure alerts for V8 heap memory usage approaching critical thresholds in production environments
- Implement logging for rejected or suspicious inputs containing unusual brace patterns
- Set up dependency scanning in CI/CD pipelines to prevent deployment of vulnerable package versions
- Monitor application logs for repeated crashes with heap allocation failures
How to Mitigate CVE-2024-4068
Immediate Actions Required
- Update the braces package to version 3.0.3 or later immediately using npm update braces or yarn upgrade braces
- Audit all projects for direct and transitive dependencies on vulnerable braces versions
- Implement input length validation at application boundaries before passing data to brace expansion functions
- Consider rate limiting on endpoints that process user-supplied patterns
Patch Information
The vulnerability is fixed in braces version 3.0.3. The fix reduces the maximum input length and improves loop handling to prevent memory exhaustion. Updates are available through standard NPM package management.
Relevant vendor resources:
Workarounds
- Implement input validation to limit string length before processing with braces
- Validate that input contains balanced braces before passing to the parser
- Set Node.js memory limits using --max-old-space-size flag to limit blast radius of exploitation
- Consider alternative brace expansion libraries if immediate patching is not feasible
# Update braces package to patched version
npm update braces@^3.0.3
# Or use yarn
yarn upgrade braces@^3.0.3
# Verify installed version
npm list braces
# Run security audit
npm audit fix
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
