CVE-2026-109558 in EdgeEver
Summary
by MITRE • 10/13/2026
EdgeEver 1.6.0 through 1.112.0 contains a stored cross-site scripting vulnerability in TemplatesPane.tsx that renders template contentMarkdown with raw HTML via dangerouslySetInnerHTML without sanitization. Attackers can write templates containing HTML event handlers through an API or MCP token to run script on preview and access the privileged window.edgeeverDesktop bridge.
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Analysis
by VulDB Data Team • 10/13/2026
The identified vulnerability represents a critical security flaw within EdgeEver versions 1.6.0 through 1.112.0, specifically located in the TemplatesPane.tsx component of the application's frontend architecture. This issue is classified as a Stored Cross-Site Scripting (XSS) vulnerability, which falls under CWE-79: Improper Neutralization of Input During Web Page Generation. The root cause lies in the implementation of template rendering logic, where user-supplied content defined within templates is processed using React's dangerouslySetInnerHTML property without any prior sanitization or validation steps. This architectural decision allows raw HTML to be injected directly into the Document Object Model (DOM), bypassing standard security controls that would typically escape special characters and neutralize malicious payloads before execution.
The operational impact of this vulnerability is severe due to the specific context in which it operates. Attackers can exploit this flaw by crafting malicious templates containing embedded HTML event handlers, such as onerror or onload attributes, and submitting them through an API endpoint or via a Model Context Protocol (MCP) token. Because the vulnerability is stored, the malicious payload persists within the application's data store rather than being transient in a URL parameter. Consequently, whenever another user or system component triggers the preview function for these templates, the browser executes the injected JavaScript code immediately upon rendering. This persistence mechanism significantly increases the attack surface and likelihood of successful exploitation compared to reflected XSS variants.
The severity is further amplified by the application's integration with desktop-specific features through a privileged bridge interface known as window.edgeeverDesktop. In typical web applications, XSS attacks are often limited to stealing session cookies or performing actions on behalf of the victim within the browser sandbox. However, in this Electron-based environment, the presence of an exposed IPC (Inter-Process Communication) bridge allows executed scripts to interact directly with the host operating system and application internals. An attacker leveraging this vulnerability can bypass web security boundaries entirely, potentially accessing sensitive local files, executing arbitrary commands on the user's machine, or manipulating the desktop application state in ways that are not restricted by standard Same-Origin Policy protections. This aligns with ATT&CK technique T1059: Command and Scripting Interpreter, as well as potential privilege escalation vectors where client-side code gains elevated privileges through exposed APIs.
Mitigation strategies must focus on eliminating the use of dangerouslySetInnerHTML for untrusted data sources or implementing rigorous sanitization before rendering. The development team should adopt a library such as DOMPurify to sanitize HTML content prior to insertion into the DOM, ensuring that all dangerous tags and attributes are stripped out while preserving legitimate formatting. Alternatively, the architecture could be refactored to use React's default JSX expression syntax for data display, which automatically escapes values and prevents script execution. Furthermore, it is critical to audit the window.edgeeverDesktop bridge implementation to ensure that sensitive operations require explicit user consent or additional authentication checks before being executed by scripts originating from web views. Implementing a Content Security Policy (CSP) with strict directives can also serve as an effective defense-in-depth measure, restricting the sources from which scripts can be loaded and preventing inline script execution even if sanitization fails.