Trilium Notes, a hierarchical note-taking application, disables authentication for its Clipper API when it detects an Electron environment. This flaw allows unauthenticated users to call endpoints such as /api/clipper/notes without a password, API token, or CSRF protection, exposing the full set of notes and related data. Consequently an attacker can read, modify, or delete data, launch phishing attacks, or potentially compromise the local system. The weakness is an intentional removal of authentication middleware for a specific technical context, corresponding to CWE‑284 (Improper Authorization) and CWE‑306 (Missing Authentication)

The vulnerability exists in Trilium Notes desktop builds up to and including version 0.102.1, specifically in the Electron-based Clipper API used in v0.101.3. The fix was backported in version 0.102.2. The affected vendor is TriliumNext.

The CVSS score of 8.6 reflects a high severity authentication bypass. EPSS information is not available, and the vulnerability is not listed in the CISA KEV catalog, so the exact exploitation probability is unknown. The attack vector is likely local network based; an attacker can scan shared networks for the high-range ports Trilium binds to (often around 37840), query the handshake endpoint to verify a Trilium instance, and then access data without credentials. The combination of local network access and the lack of authentication makes this a significant exploitation risk for users on shared or public networks.