CVE-2026-77438

Trilium Notes, an open-source self-hosted hierarchical note-taking application, fails to enforce per-note access controls in its public share-search endpoint in all versions up to and including 0.103.0. An unauthenticated visitor can submit a search against a shared ancestor note, and the endpoint runs a full-text search across the entire published subtree and returns each matching note's title, share identifier, and hierarchical path without re-checking that note's shareCredentials (password) or shareHiddenFromTree settings. Because the search matches on note content, an attacker can enumerate protected notes and use the endpoint as a boolean oracle that confirms arbitrary substrings, effectively reconstructing the full contents of notes that are supposed to be gated behind a password. Any Trilium deployment running version 0.103.0 or earlier that publishes notes through the public share feature is affected, particularly those relying on per-note passwords or hidden-from-tree flags. No public proof-of-concept or known exploitation has been reported; EPSS puts the 30-day exploitation probability at a low 0.2%, and the issue is not listed in CISA's KEV catalog.

What to do: Upgrade Trilium Notes to version 0.104.0 or later, which re-enforces shareCredentials and shareHiddenFromTree checks in the share-search path. Until patched, avoid publicly sharing subtrees that contain password-protected or hidden notes, or disable the public share feature for sensitive content. After upgrading, verify that the public search endpoint no longer returns titles, paths, or content for password-protected and hidden shared notes.