CVE-2026-88976 in Plate
Summary
by MITRE • 09/16/2026
Plate is a rich-text editor with AI and shadcn/ui. Prior to 53.3.11, and in the discontinued 54.0.0-beta.0 through 54.0.0-beta.1 builds, Plate core HTML deserialization APIs parse supplied HTML strings in the active document. When an application passes untrusted or cross-user HTML to these APIs, certain HTML attributes can trigger browser behavior before the HTML is converted into editor nodes. This can allow attacker-controlled script to execute in the consuming application's origin when another user loads the deserialized content. This issue is fixed in version 53.3.11.
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Analysis
by VulDB Data Team • 09/16/2026
The vulnerability identified within the Plate rich-text editor framework represents a critical server-side input validation failure that leads to client-side code execution, specifically classified under CWE-79: Improper Neutralization of Input During Web Page Generation (Cross-site Scripting). This flaw exists in versions prior to 53.3.11 and affects specific beta builds ranging from 54.0.0-beta.0 through 54.0.0-beta.1, which are now discontinued but may still be present in legacy systems or unpatched deployments. The core issue stems from the library's HTML deserialization APIs, which are designed to parse raw HTML strings and convert them into internal editor nodes for rendering within the application interface.
The technical root cause lies in the premature execution of browser-native behaviors before the sanitization process is complete. When an application passes untrusted or cross-user HTML content to these specific Plate core APIs, certain maliciously crafted HTML attributes are interpreted by the user's web browser immediately upon parsing. This occurs because the deserialization logic processes the raw DOM structure before applying necessary security filters or converting the data into safe editor nodes. Consequently, if a victim user loads content containing this malformed HTML, their browser will execute any embedded script tags or event handlers contained within those attributes.
The operational impact of this vulnerability is severe cross-site scripting (XSS), which allows an attacker to inject arbitrary JavaScript code that runs in the context of the consuming application's origin. This means the malicious scripts have access to all cookies, local storage tokens, session identifiers, and other sensitive data associated with the victim user's account on the Plate-based platform. An attacker could exploit this to hijack user sessions, perform actions on behalf of the victim such as modifying settings or deleting content, or even redirecting users to phishing sites. The attack vector typically involves an adversary crafting a malicious HTML payload that is then shared within the rich-text editor, relying on another authorized user to view and load the deserialized content for the script to execute.
From a threat intelligence perspective, this vulnerability aligns with MITRE ATT&CK technique T1059.007: Command and Scripting Interpreter via JavaScript (Web Browser), as it leverages browser-based scripting capabilities to achieve unauthorized execution. It also relates to CWE-83: Improper Neutralization of Script-Related HTML Tags in a Web Page, highlighting the failure to properly sanitize script-related elements during the input processing phase. The distinction here is that the vulnerability arises not from direct user input into an XSS-prone field, but from the internal API's handling of deserialized content, which may be sourced from other users or external systems.
To mitigate this risk, organizations must immediately upgrade to version 53.3.11 or later, where the parsing logic has been corrected to ensure that HTML attributes are sanitized before any browser behavior is triggered. For applications unable to update immediately due to dependency constraints, a temporary workaround involves implementing strict server-side sanitization of all incoming HTML content using robust libraries such as DOMPurify before passing it to Plate's deserialization APIs. Additionally, developers should audit their codebase for direct usage of the affected core HTML deserialization functions and replace them with safer alternatives that enforce context-aware escaping. Regular security audits focusing on rich-text editor integrations are recommended to identify similar patterns where raw HTML is processed without adequate neutralization of dynamic content.