SiYuan before v3.7.4 improperly restricts excessive authentication attempts in the CheckAuth() middleware. The HTTP Basic Authentication branch, which guards nearly the entire /api/* surface, accepts the workspace access code (Conf.AccessAuthCode) as the Basic Auth password but never consults the CAPTCHA/lockout gate or increments the failure counter used by the cookie/session login path. This allows unauthenticated remote attackers to brute-force the admin access code with unlimited automated requests and obtain full RoleAdministrator access to the kernel. A secondary weakness exists because the access code is compared using a non-constant-time string comparison.

SiYuan versions before v3.7.4 fail to validate or escape the color field in attribute-view select options, allowing stored cross-site scripting through eight unescaped render sites. Attackers can inject event-handler attributes by including quotation marks in the color value, executing arbitrary JavaScript when viewing databases containing the malicious select field.

SiYuan before 3.7.4 contains an improper restriction of excessive authentication attempts vulnerability in the authFilePublishAccess endpoint that allows unauthenticated attackers to brute-force per-notebook publish passwords. Attackers can submit unbounded password guesses without rate limiting or CAPTCHA to gain access to password-protected published notebooks.

SiYuan versions before v3.7.4 contain an information disclosure vulnerability in the getAttributeViewBacklinks endpoint that consults the forbidden access list instead of the visibility list when filtering backlinks. Anonymous readers can supply a publicly visible database row identifier to discover hidden-tier documents that reference it, receiving the database name, row title, and document path of hidden documents.

SiYuan versions <= v3.7.2 contain a SQL injection vulnerability in the backlink/mention search query (kernel/model/backlink.go), which concatenates stored block metadata (title, name, alias, anchor text) and the client-supplied keyword into a SQL MATCH/search statement while escaping only the double-quote character and not the single quote. A single quote in the client keyword (first-order, reachable by an anonymous or RoleReader user on the publish surface) or in stored document metadata (second-order) breaks out of the string literal. Because the query runs on the main read-write siyuan.db handle via a statement-stacking-capable driver, an attacker can execute arbitrary SQL, enabling cross-notebook read and write. Fixed in v3.7.4.

SiYuan versions before v3.7.4 contain a publish-boundary bypass vulnerability in WebSocket broadcast sessions that allows anonymous readers to receive unfiltered edits. Attackers can establish a WebSocket connection to the publish surface and passively receive real-time content events including password-protected and forbidden documents without authentication.

SiYuan versions before v3.7.4 contain a missing authorization vulnerability in the /api/ref/refreshBacklink endpoint that allows anonymous readers to trigger persistent server-side writes. Attackers can invoke the endpoint with an attacker-controlled block ID to flush transaction queues, scan all references globally, and enqueue database writes, bypassing read-only protections and enabling resource amplification attacks.

SiYuan versions before v3.7.4 contain an information disclosure vulnerability in the getRefIDsByFileAnnotationID endpoint that returns block identifiers citing PDF annotations without publish-access filtering. Attackers can extract block identifiers from restricted documents by supplying annotation identifiers visible in published pages, revealing citation relationships across forbidden and password-protected tiers.

SiYuan before v3.7.4 contains an information disclosure vulnerability in the /api/filetree/authFilePublishAccess endpoint, which is registered with CheckAuth only and is reachable anonymously. The endpoint never sets a failure code, so its outcome is signalled entirely by the response message and by the presence of a Set-Cookie header, and these signals differ across access tiers. By submitting requests with an empty password for a candidate document identifier, an anonymous attacker can distinguish whether a document is public/nonexistent, password-protected, or exists at the hidden or forbidden tier, thereby confirming the existence of documents they are not permitted to access. Because hidden and forbidden entries store an empty password, such requests also cause the server to issue a publish-auth cookie for forbidden documents.

SiYuan versions before v3.7.4 contain an information disclosure vulnerability in the getBookmarkLabels endpoint that returns all bookmark labels in the workspace without publish-access filtering. Anonymous readers and publish-mode readers can obtain the complete bookmark vocabulary across the workspace, disclosing subject matter and organizational information from inaccessible documents.