GHSA-56mp-4f3v-fgj2 SiYuan: Stored XSS to RCE via Unsanitized Attribute View Asset Cell Content
SiYuan v3.6.5 and earlier versions contain a stored cross-site scripting (XSS) vulnerability in the Attribute View (database) asset cell renderer that escalates to remote code execution (RCE) in the Electron desktop client. This is a neighbor-bug of CVE-2026-44588: the fix for -44588 used `escapeAriaLabel()` (double-escapes `<`), but the AV asset renderers were left using the weaker `escapeAttr()` (escapes only quotes) or no escaping at all.Vulnerability DetailsThe Electron renderer is configured with `nodeIntegration: true` and `contextIsolation: false` (app/electron/main.js:307), allowing any JavaScript executing in the renderer to directly access Node.js APIs including `require('child_process')`.Two XSS sinks exist.Sink 1 (Direct Stored XSS - triggers on page load)`app/src/protyle/render/av/cell.ts:1008`:data-url="${escapeAttr(item.content)}">${item.name || item.content}</span>`;The `>${item.name || item.content}</span>` portion is raw user input with zero escaping.`app/src/protyle/render/av/blockAttr.ts:93` (even worse - completely unescaped):Rendered via `action.ts:860`: `cellElement.innerHTML = renderCell(...)` results in immediate XSS on page load.Sink 2 (Hover-triggered XSS via aria-label round-trip)Same lines emit `aria-label="${escapeAttr(item.content)}"` on `.ariaLabel` elements.`escapeAttr()` (util/escape.ts:14) escapes only `"` and `'` — NOT `<` or `>`.`popover.ts:33` global mouseover handler reads `aria-label` via `getAttribute` (which attribute-decodes entities).Line 144: `showTooltip(decodeURIComponent(tip), ...)` then `tooltip.ts:41`: `messageElement.innerHTML = message` results in XSS on hover.Source`app/src/protyle/render/av/asset.ts:405`: `addAssetLink()` reads user input from a free-form `<textarea>` with no sanitization.Kernel stores `MAsset.Content` raw (kernel/av/value.go:53), no server-side sanitization.Attack VectorAttacker creates a malicious note containing an Attribute View (database).Attacker adds an asset cell with link content: `<img src=x onerror=require('child_process').exec('calc')>`Victim opens the note for immediate RCE (Sink 1), or hovers over the cell for RCE (Sink 2).In a sync/collaboration scenario, the malicious note propagates to all users.Proof of ConceptPayload (Direct XSS) — in an AV asset cell link field, enter:For RCE in Electron desktop:Steps to ReproduceOpen SiYuan desktop app (v3.6.5).Create a new document.Insert an Attribute View (database): `/` then select "Table".Add a column of type "Asset".Click the asset cell, then "Add Link".In the "Link" textarea, paste: `<img src=x onerror=alert(1)>`Leave "Title" empty or fill with benign text.Click outside the dialog to save.Observe: Alert fires immediately (Sink 1). Hovering over the cell also triggers (Sink 2).ImpactRemote Code Execution on victim's system via malicious note sync/import.Data exfiltration: attacker can read all notes, access filesystem, steal credentials.Persistence: malicious payload stored in `.sy` files, executes on every open.Suggested FixReplace `escapeAttr()` with `escapeAriaLabel()` for all `aria-label` attributes in AV cell renderers.Escape `item.name` and `item.content` with `escapeHtml()` before concatenating into element text content.Affected files: `app/src/protyle/render/av/cell.ts`, `app/src/protyle/render/av/blockAttr.ts`, `app/src/protyle/render/av/asset.ts`.Additional ContextThis vulnerability is a neighbor-bug of CVE-2026-44588. The fix for -44588 correctly used `escapeAriaLabel()` (which double-escapes `<` to survive the attribute -> `getAttribute` -> `innerHTML` round-trip), but the AV asset cell renderers were left using the weaker `escapeAttr()` or no escaping. This is part of a pattern of incomplete fixes in SiYuan (see also CVE-2026-33066, CVE-2026-29183). The long-term fix should set Electron`contextIsolation: true` and `nodeIntegration: false`.ReportReporter (GitHub: Yunkaiwjs).
CVSS v3.1 score: 9.9