RCE in B3log Siyuan
CVE-2026-34448
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 <img src="..."> 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.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.007 (52.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 52.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.007 · change: +0.002
Affected products
- B3log Siyuan
- Siyuan-Note Siyuan — versions < 3.6.2
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-rx4h-526q-4458 (Exploit, Vendor Advisory)
- github.com/siyuan-note/siyuan/issues/17246 (Issue Tracking)
- github.com/siyuan-note/siyuan/releases/tag/v3.6.2 (Release Notes)
Frequently asked questions
- What is CVE-2026-34448?
- CVE-2026-34448 is a critical-severity vulnerability in B3log Siyuan, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2026-03-31.
- How severe is CVE-2026-34448?
- Critical severity. CVSS v3 base score is 9.0 out of 10.