SiYuan - Remote Code Execution via Malicious Bazaar Package Metadata and README

An attacker publishes a malicious package to the SiYuan Bazaar marketplace with XSS payloads embedded in the package `displayName`, `description`, or `README.md` fields [ref_id=1]. When any user browses the Bazaar listing page, the metadata payload executes automatically (zero-click) because the template literal interpolation does not escape HTML [CWE-79]. If the user clicks to view the package README, the `renderREADME` function renders raw HTML without sanitization and the frontend assigns it to `innerHTML`, triggering a second XSS vector (one-click) [ref_id=1]. Because Electron runs with `nodeIntegration: true` and `contextIsolation: false`, the injected JavaScript can call `require('child_process').exec()` to execute arbitrary OS commands, achieving full remote code execution.

The vulnerability spans three locations: metadata rendering in `app/src/config/bazaar.ts:275-277` where `displayName` and `description` are injected into HTML without escaping; the backend README renderer in `kernel/bazaar/package.go:635-645` which creates a Lute engine without calling `SetSanitize(true)`; and the frontend README display in `app/src/config/bazaar.ts:607` which assigns unsanitized HTML to `innerHTML`. The Electron configuration at `app/electron/main.js:422-426` enables `nodeIntegration: true`, which turns the XSS into full RCE.

The patch must address three gaps. First, user-controlled metadata (`displayName`, `description`) must be passed through an HTML-escape function before being interpolated into template literals in `bazaar.ts` [ref_id=1]. Second, the Lute engine instance in `package.go` must call `SetSanitize(true)` so that raw HTML embedded in markdown is stripped during the `Md2HTML` conversion, matching the behavior already used in the note renderer at `kernel/util/lute.go:81` [ref_id=1]. Third, as a long-term hardening measure, the Electron `webPreferences` should disable `nodeIntegration` and enable `contextIsolation` and `sandbox` to prevent XSS from escalating to RCE even if a sanitization bypass occurs.