CVE-2026-34448: SiYuan: Stored XSS in Attribute View Gallery/Kanban Cover Rendering Allows Arbitrary Command Execution in Desktop Client

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.7%, percentile 54: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 54% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes github.com/siyuan-note/siyuan/kernel (Go) <= 3.6.1, fixed in 3.6.2. Check your lockfile, including transitive dependencies.

What it is

SiYuan is a personal knowledge management system. Prior to version 3.6.2, an attacker who can place a malicious URL in an Attribute View mAsse field can trigger stored XSS when a victim opens the Gallery or Kanban view with “Cover From -> Asset Field” enabled. The vulnerable code accepts arbitrary http(s) URLs without extensions as images, stores the attacker-controlled string in coverURL, and injects it directly into an attribute without escaping. In the Electron desktop client, the injected JavaScript executes with nodeIntegration enabled and contextIsolation disabled, so the XSS reaches arbitrary OS command execution under the victim’s account. This issue has been patched in version 3.6.2.

From the GitHub advisory

Summary An attacker who can place a malicious URL in an Attribute View mAsse field can trigger stored XSS when a victim opens the Gallery or Kanban view with “Cover From -> Asset Field” enabled. The vulnerable code accepts arbitrary http(s) URLs without extensions as images, stores the attacker-controlled string in coverURL, and injects it directly into an attribute without escaping. In the Electron desktop client, the injected JavaScript executes with nodeIntegration enabled and contextIsolation disabled, so the XSS reaches arbitrary OS command execution under the victim’s account.

Details The vulnerable flow is:

1. IsPossiblyImage(assetPath) accepts arbitrary http(s) URLs without validating that they are safe image URLs. 2. When an Attribute View card uses Cover From -> Asset Field, the application copies asset.Content directly into galleryCard.CoverURL / kanbanCard.CoverURL. 3. The front-end renderer inserts coverURL directly into without escaping quotes or other attribute-breaking characters. 4. A payload such as https://example.com/" onerror="require('childprocess').exec('calc') breaks out of the src attribute and adds an attacker-controlled onerror handler. When the image fails to load, the injected JavaScript runs in the Electron renderer. Because the desktop app enables nodeIntegration: true and disables contextIsolation and webSecurity, that JavaScript can access Node.js APIs and execute system commands.

PoC 1. Install Electron Desktop app. 2. Create a database / Attribute View with an mAsset column and add at least one row. 3. Add any legitimate image to that mAsset field so the entry is stored as type image. 4. Switch the view to Gallery or Kanban. 5.Set Cover From to Asset Field and choose the mAsset column. 6. Edit the existing image asset entry and replace its link with the following payload:

7. Save the change and reopen or refresh the Gallery / Kanban view. 8. Observe that the rendered HTML contains an injected onerror handler and the Calculator application starts on Windows.

Weakness type: CWE-79, CWE-94.

Product: github.com/siyuan-note/siyuan/kernel (Go) · Assigned by: GitHub_M · Published: 2026-03-31

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: low (any account)
• User interaction: required (a user must click/open something)
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.73% probability of exploitation activity in the next 30 days; percentile 54.

Timeline

• 2026-03-31 — CVE record published by GitHub_M
• 2026-03-31 — GitHub-reviewed advisory GHSA-rx4h-526q-4458 published (critical)
• 2026-04-03 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-rx4h-526q-4458 github.com
2. CVE.org record CVE-2026-34448 cve.org
3. NVD entry CVE-2026-34448 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com

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