6.8
MEDIUM CVSS 3.1
CVE-2026-39311
Trilium Notes: Stored XSS Leads to Unauthorized Remote Code Execution (RCE) via Unsanitized SVG Attachments
Description

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.

INFO

Published Date :

May 20, 2026, 8:16 p.m.

Last Modified :

May 20, 2026, 8:16 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-39311 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM [email protected]
Solution
Update Trilium Notes to version 0.102.2 or later to patch the SVG sanitization and CSP misconfiguration.
  • Update Trilium Notes to version 0.102.2.
  • Ensure SVG sanitization is enabled.
  • Configure a strict Content Security Policy.
  • Restrict access to the backend execution API.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-39311.

URL Resource
https://github.com/TriliumNext/Trilium/releases/tag/v0.102.2
https://github.com/TriliumNext/Trilium/security/advisories/GHSA-p837-cxw3-m964
https://github.com/TriliumNext/Trilium/security/advisories/GHSA-p837-cxw3-m964
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-39311 is associated with the following CWEs:

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-39311 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-39311 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    May. 20, 2026

    Action Type Old Value New Value
    Added Description 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.
    Added CVSS V3.1 AV:N/AC:H/PR:H/UI:R/S:C/C:L/I:L/A:H
    Added CWE CWE-79
    Added CWE CWE-94
    Added Reference https://github.com/TriliumNext/Trilium/releases/tag/v0.102.2
    Added Reference https://github.com/TriliumNext/Trilium/security/advisories/GHSA-p837-cxw3-m964
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    May. 20, 2026

    Action Type Old Value New Value
    Added Reference https://github.com/TriliumNext/Trilium/security/advisories/GHSA-p837-cxw3-m964
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.