Important Security Flaw Patched in Apache ECharts Library

Apache ECharts is a free, powerful JavaScript charting and visualization library that developers use globally. Recently, security experts uncovered a flaw within its tooltip rendering component. Specifically, this Apache ECharts XSS vulnerability tracks as CVE-2026-45249 and carries an important severity rating. The security flaw allows malicious actors to run arbitrary code on a user’s browser. Consequently, maintainers urge web developers to review their visual applications immediately to prevent exploitation.

Understanding the Tooltip Flaw

Technical Root Cause

The issue specifically resides within the library’s Lines series tooltip rendering logic. In versions prior to 6.1.0, the software fails to sanitize input strings properly. For instance, this bug triggers if developers use both Lines series and tooltips without a user-defined formatter. If a developer specifies a data name, the application processes that raw text directly. As a result, the system renders the raw HTML string through an innerHTML sink into the tooltip content.

Breaking Security Conventions

Conventionally, the built-in tooltip formatters perform HTML escaping automatically to protect applications. However, this specific case completely breaks that helpful safety design. Because the code bypasses data sanitization, it unexpectedly leads to malicious script execution when the browser displays tooltips. For example, bad actors can steal session tokens or hijack user accounts. Attackers can therefore exploit this slip to compromise enterprise environments.

Impact and Mandatory Remediation

Recommended Update Actions

Fortunately, the development team has addressed this risk in the latest product release. To fix the issue, the team recommends that users upgrade to version 6.1.0 if they utilize the Lines series. This software upgrade corrects the innerHTML behavior and properly escapes user inputs. In addition, the fix eliminates the vulnerability without impacting your existing chart customization options.

Securing Your Products

Consequently, applying this update ensures that your interactive charts remain highly customizable and secure. Ultimately, fixing this Apache ECharts XSS vulnerability promptly protects your commercial products from cross-site scripting risks.