EUVD-2026-39128Published

SiYuan: Stored XSS to RCE via Unsanitized Attribute View Asset Cell Content

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

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

cve-program · CVE-2026-50551

Published

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

Source published: 24 Jun 2026 21:20:42 UTC
Source modified: 25 Jun 2026 13:20:40 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

euvd · EUVD-2026-39128

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Jun 24, 2026, 9:20:42 PM

dateUpdated: Jun 25, 2026, 1:20:40 PM

Source published: Jun 24, 2026, 9:20:42 PM (timezone not stated)
Source modified: Jun 25, 2026, 1:20:40 PM (timezone not stated)
Observed here: 7 Nov 2026 11:34:16 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

nvd · CVE-2026-50551

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Deferred

Weakness classifications: CWE-79

Original publisher date fields

published: 2026-06-24T22:16:47.513

lastModified: 2026-10-25T23:10:00.167

Source published: 24 Jun 2026 22:16:47 UTC
Source modified: 25 Oct 2026 23:10:00 UTC
Observed here: 27 Oct 2026 14:13:17 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

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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

osv · GHSA-56mp-4f3v-fgj2

Published

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 Details The 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`: text += `<span class="b3-chip av__celltext--url ariaLabel" aria-label="${escapeAttr(item.content)}" data-name="${escapeAttr(item.name)}" data-url="${escapeAttr(item.content)}">${item.name || item.content}</span>`; The `>${item.name || item.content}</span>` portion is raw user input with zero escaping. `app/src/protyle/render/av/blockAttr.ts:93` (even worse - completely unescaped): html += `<img loading="lazy" class="av__cellassetimg ariaLabel" aria-label="${item.content}" src="${getCompressURL(item.content)}">`; Rendered via `action.ts:860`: `cellElement.innerHTML = renderCell(...)` results in immediate XSS on page load. ### Sink 2 (Hover-triggered XSS via aria-label round-trip) - Same lines emit `aria-label="${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 Vector 1. Attacker creates a malicious note containing an Attribute View (database). 2. Attacker adds an asset cell with link content: `<img src=x onerror=require('child_process').exec('calc')>` 3. Victim opens the note for immediate RCE (Sink 1), or hovers over the cell for RCE (Sink 2). 4. In a sync/collaboration scenario, the malicious note propagates to all users. ## Proof of Concept Payload (Direct XSS) — in an AV asset cell link field, enter: <img src=x onerror=alert(document.domain)> For RCE in Electron desktop: <img src=x onerror=require('child_process').exec('calc')> ### Steps to Reproduce 1. Open SiYuan desktop app (v3.6.5). 2. Create a new document. 3. Insert an Attribute View (database): `/` then select "Table". 4. Add a column of type "Asset". 5. Click the asset cell, then "Add Link". 6. In the "Link" textarea, paste: `<img src=x onerror=alert(1)>` 7. Leave "Title" empty or fill with benign text. 8. Click outside the dialog to save. 9. Observe: Alert fires immediately (Sink 1). Hovering over the cell also triggers (Sink 2). ## Impact - Remote 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 Fix 1. Replace `escapeAttr()` with `escapeAriaLabel()` for all `aria-label` attributes in AV cell renderers. 2. 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 Context This 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`. ## Report Reporter (GitHub: Yunkaiwjs).

Source published: 10 Jul 2026 20:37:04 UTC
Source modified: 21 Jul 2026 19:19:09 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

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

Publisher rating · CRITICAL

osv · GO-2026-5967

Published

SiYuan: Stored XSS to RCE via Unsanitized Attribute View Asset Cell Content in github.com/siyuan-note/siyuan/kernel

Source published: 17 Jul 2026 19:42:05 UTC
Source modified: 21 Jul 2026 19:15:33 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

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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 · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.