CVE-2026-69083: SiYuan: Unauthenticated SQL execution and REGEXP injection via fullTextSearchAssetContent (publish mode): reader-reachable raw SQL (method 2) and unescaped REGEXP (method 3) on read-write asset-content DB

The /api/search/fullTextSearchAssetContent endpoint exposes two SQL flaws on the asset-content database, both reachable by the publish RoleReader token and by the anonymous account when Publish.Auth.Enable is false:

1. method 2 passes a client-supplied SQL statement to the read-write asset-content DB with no single-statement or read-only guard, and without the admin restriction its sibling fullTextSearchBlock applies to the same SQL method.
2. method 3 builds a REGEXP clause by concatenating the client expression with no quote-escaping, permitting SQL breakout while the equivalent block-search builder does escape.

Both run on a read-write handle through a statement-stacking-capable driver, spanning the cross-notebook asset-content store.