CVE-2026-39311 (GCVE-0-2026-39311)

Vulnerability from cvelistv5 – Published: 2026-05-20 19:13 – Updated: 2026-05-20 19:27
VLAI
Title
Trilium Notes: Stored XSS Leads to Unauthorized Remote Code Execution (RCE) via Unsanitized SVG Attachments
Summary
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.
Severity
6.8 (Medium)
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/C:L/I:L/A:H
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-05-20 19:26 UTC
CWE
  • CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
  • CWE-94 - Improper Control of Generation of Code ('Code Injection')
Assigner
GitHub_M CNA
References
Impacted products
Vendor Product Version
TriliumNext Trilium Affected: < 0.102.2
Create a notification for this product.
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