TriliumNext Trilium up to 0.102.1 Content Security Policy cross site scripting

Summaryinfo

A vulnerability was found in TriliumNext Trilium up to 0.102.1 and classified as problematic. The affected element is an unknown function of the component Content Security Policy Handler. Executing a manipulation can lead to cross site scripting. This vulnerability is tracked as CVE-2026-39311. The attack can be launched remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in TriliumNext Trilium up to 0.102.1. This vulnerability affects an unknown code of the component Content Security Policy Handler. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. CVE summarizes:

Trilium Notes is a cross-platform, hierarchical note taking application focused on building large personal knowledge bases. Versions 0.102.1 and prior contain a critical security flaw where lack of SVG sanitization combined with a disabled Content Security Policy (CSP) and a publicly reachable backend execution API results in an unauthenticated Remote Code Execution (RCE). The vulnerability arises from an insecure-by-design architecture: Trilium serves SVG attachments with the image/svg+xml MIME type without any sanitization, and it explicitly disables Helmet's Content Security Policy middleware, removing the primary defense against script execution in served assets. Because the malicious SVG runs under the Same-Origin Policy, it can issue a fetch('/') to extract the csrfToken from the document body. With that token, it can send a signed request to /api/script/exec to execute arbitrary Node.js code on the server. An attacker can compromise the entire server instance simply by tricking an authenticated user into viewing a shared SVG attachment. The issue has been fixed in version 0.102.2.

The advisory is available at github.com. This vulnerability was named CVE-2026-39311 since 04/06/2026. The exploitation appears to be difficult. The attack can be initiated remotely. Additional levels of successful authentication are required for exploitation. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1059.007 by the MITRE ATT&CK project.

Upgrading to version 0.102.2 eliminates this vulnerability.

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Productinfo

Vendor

• TriliumNext

Name

• Trilium

Version

• 0.102.0
• 0.102.1

Website

• Product: https://github.com/TriliumNext/Trilium/

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CPE 2.2info

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