Trilium Notes: Stored XSS Leads to Unauthorized Remote Code Execution (RCE) via Unsanitized SVG Attachments

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Summary

CVECVE-2026-39311
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-20 20:16:39 UTC
Updated2026-05-21 15:24:25 UTC
DescriptionTrilium 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.

Risk And Classification

Primary CVSS: v3.1 6.8 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/C:L/I:L/A:H

EPSS: 0.001260000 probability, percentile 0.313340000 (date 2026-05-27)

Problem Types: CWE-79 | CWE-94 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | CWE-94 CWE-94: Improper Control of Generation of Code ('Code Injection')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/C:L/I:L/A:H
3.1CNADECLARED6.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/C:L/I:L/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
High
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
High

CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/C:L/I:L/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA TriliumNext Trilium affected < 0.102.2 Not specified

References

ReferenceSourceLinkTags
github.com/TriliumNext/Trilium/releases/tag/v0.102.2 [email protected] github.com
github.com/TriliumNext/Trilium/security/advisories/GHSA-p837-cxw3-m964 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
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