CoreUI for Angular v5.6.21 - Angular 21.2.5 Security Update

Monday, March 23, 2026

We are pleased to announce the release of CoreUI for Angular v5.6.21. This critical security update brings full support for Angular 21.2.5 and includes important security patches addressing multiple vulnerabilities in flatted, socket.io-parser, and undici packages. This update ensures your Angular applications run securely with the latest framework improvements and comprehensive dependency updates.

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How to Update

To update to CoreUI v5.6.21 for Angular 21.2.5, follow these simple steps to ensure your project is up-to-date:

Verify that you are using a supported version of node.js before you upgrade your application. Angular v21 supports node.js versions: v18.19 and newer, or v20.11 and newer, or v22.0 and newer.
To update your application to Angular v21.2.5 and CoreUI v5.6.21, in the application’s project directory, run:

ng update @angular/[email protected] @angular/[email protected] @coreui/coreui@~5.6.0 @coreui/angular@~5.6.21

Please ensure that there are no error messages in the results.
See also:
- CoreUI for Angular Installation
- CoreUI for Angular versions

What’s New

Angular Framework Update

CoreUI for Angular v5.6.21 fully supports Angular 21.2.5, bringing you the latest framework patches:

Security Fixes: Critical security patches from the Angular team
Stability Updates: Framework-level bug fixes and improvements
Performance: Runtime optimizations and enhancements
Compatibility: Enhanced compatibility with Angular ecosystem and TypeScript

Critical Security Patches

This release addresses three important security vulnerabilities to ensure your applications are protected:

1. Flatted Library Vulnerability (GHSA-rf6f-7fwh-wjgh)

Patched a critical security issue in the flatted serialization library. This vulnerability could potentially be exploited in applications that use flatted for data serialization.

2. Socket.io-parser Vulnerability (GHSA-677m-j7p3-52f9)

Resolved a security advisory in socket.io-parser that could affect applications using Socket.io for real-time communication.

3. Undici Package - Multiple Security Issues

Updated undici to version ^7.24.2 to address six critical security vulnerabilities:

WebSocket Parsing Vulnerabilities: Fixed parsing issues that could lead to security exploits
HTTP Smuggling Concerns: Addressed potential HTTP request smuggling attacks
Memory Consumption Weaknesses: Resolved memory exhaustion vulnerabilities
WebSocket Validation Gaps: Enhanced WebSocket connection validation
CRLF Injection Risks: Mitigated CRLF injection attack vectors

We strongly recommend updating as soon as possible to protect your applications against these known vulnerabilities and ensure compliance with security best practices.

Development Tooling Updates

Updated Angular and development tools to the latest versions:

Angular Core and CLI: Full support for Angular 21.2.5
Build Tools: Updated @angular-devkit/schematics, @angular/build, and @angular/cli
Component Development Kit: Latest @angular/cdk
Code Quality: Updated angular-eslint and typescript-eslint packages
Package Management: Updated ng-packagr for better library builds

Dependency Updates

We have updated key dependencies to their latest versions, ensuring improved performance, security, and compatibility with the latest Angular 21.2.5 standards:

Angular Core Updates

@angular/animations from: 21.2.3 to: 21.2.5
@angular/common from: 21.2.3 to: 21.2.5
@angular/compiler from: 21.2.3 to: 21.2.5
@angular/core from: 21.2.3 to: 21.2.5
@angular/forms from: 21.2.3 to: 21.2.5
@angular/platform-browser from: 21.2.3 to: 21.2.5
@angular/platform-browser-dynamic from: 21.2.3 to: 21.2.5
@angular/router from: 21.2.3 to: 21.2.5

Angular Development Tools

@angular-devkit/schematics from: 21.2.2 to: 21.2.3
@angular/build from: 21.2.2 to: 21.2.3
@angular/cli from: 21.2.2 to: 21.2.3
@angular/cdk from: 21.2.2 to: 21.2.3
@angular/compiler-cli from: 21.2.3 to: 21.2.5

Build and Package Management Tools

ng-packagr from: 21.2.2 to: 21.2.3
@angular-eslint/builder from: 19.0.1 to: 19.0.2
@angular-eslint/eslint-plugin from: 19.0.1 to: 19.0.2
@angular-eslint/eslint-plugin-template from: 19.0.1 to: 19.0.2
@angular-eslint/schematics from: 19.0.1 to: 19.0.2
@angular-eslint/template-parser from: 19.0.1 to: 19.0.2

Code Quality and Linting

eslint from: 9.19.0 to: 9.20.0
typescript-eslint from: 8.57.0 to: 8.58.0

Security Overrides

undici - overridden to: ^7.24.2 (addresses six critical vulnerabilities)

These updates bring your application to the latest Angular 21.2.5 and related library versions.

Released Packages

This release includes updates to the following CoreUI Angular packages:

@coreui/angular: v5.6.21 - Core Angular components and directives
@coreui/angular-chartjs: v5.6.21 - Chart.js integration for Angular
@coreui/icons-angular: v5.6.21 - CoreUI Icons for Angular

All packages are synchronized to version 5.6.21 to ensure compatibility and consistent behavior across the CoreUI Angular ecosystem.

Migration Notes

This is a security and maintenance release with full backward compatibility. No breaking changes were introduced. If you’re upgrading from an earlier version:

Update your dependencies using the ng update command shown above
Review your application for any console warnings
Run your test suite to ensure everything works as expected
Verify security patches by running npm audit to check for vulnerabilities

Why Update?

Updating to CoreUI for Angular v5.6.21 provides critical benefits:

Security: Critical patches for three major vulnerabilities (flatted, socket.io-parser, undici)
Latest Angular Features: Access to Angular 21.2.5 improvements
Stability: Framework-level bug fixes and enhancements
Best Practices: Stay current with latest security standards
Compatibility: Synchronized package versions prevent conflicts
Support: Remain on officially supported versions

Security Recommendations

After updating:

Verify Patches: Ensure all vulnerabilities are resolved by running npm audit
Test Thoroughly: Verify all functionality, especially WebSocket and real-time features
Review Dependencies: Check for any additional security advisories
Update Regularly: Keep your dependencies up to date with regular maintenance
Monitor Advisories: Subscribe to security advisories for Angular and CoreUI

Additional Resources

For a comprehensive overview of all changes, enhancements, and updates introduced in this release, please refer to the full changelog on GitHub.