CVE-2026-91021

CVE-2026-91021

Published Sep 14, 2026 CVSS 3.1 · 5.4 Medium EPSS < 1% KEV · Not listed
Description
Trilium Notes, version v0.103.0 and earlier, contains a stored cross-site scripting (XSS) vulnerability in the share renderer for webView notes due to improper HTML escaping of user-controlled #webViewSrc values. This vulnerability allows attackers with note-authoring privileges to inject arbitrary JavaScript that executes for any user who opens the shared note, including administrators.

Analysis

AI-generated

Technical impact

Trilium Notes introduced a stored cross‑site scripting flaw in the share renderer for webView notes. The vulnerability arises from inadequate HTML escaping of the user‑controlled #webViewSrc parameter, allowing a note author to inject malicious JavaScript. When any user—including administrators—opens the compromised note, the injected code runs in the context of the victim’s browser, potentially leading to data theft, credential compromise, or the execution of arbitrary client‑side instructions.

Affected Systems

Trilium Notes versions 0.103.0 and earlier are affected. The flaw affects any installation that utilizes the share renderer to publish notes via webView, regardless of deployment environment.

Risk and Exploitability

The CVSS score of 5.4 indicates moderate severity, and there is no EPSS score available. The flaw is not listed in the CISA KEV catalog. Attackers need only note‑authoring privileges to embed the payload, and the exploitation occurs when a target user opens the shared note. The path is internal to the application, requiring no external network interaction beyond the share action.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Upgrade Trilium Notes to a version newer than 0.103.0 where the input sanitisation is fixed.
  • If an upgrade is not immediately possible, restrict note‑authoring privileges or disable the webView share renderer until a patch is applied.
  • Implement a strict Content‑Security‑Policy for the webView to block the execution of injected scripts and mitigate potential damage.

Generated by OpenCVE AI on September 15, 2026 at 12:47 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Description Trilium Notes, version v0.103.0 and earlier, contains a stored cross-site scripting (XSS) vulnerability in the share renderer for webView notes due to improper HTML escaping of user-controlled #webViewSrc values. This vulnerability allows attackers with note-authoring privileges to inject arbitrary JavaScript that executes for any user who opens the shared note, including administrators.
Title CVE-2026-91021
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Subscriptions

No data.

Weaknesses
  • CWE-79

    Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Sources

Status
PUBLISHED
Assigner
certcc
Published
Updated
Sep 14, 2026, 7:41 PM
Reserved
Sep 14, 2026, 5:02 PM
Status
Deferred
Published
Sep 14, 2026, 6:20 PM
Modified
Sep 16, 2026, 1:42 PM