Vulnerability in B3log Siyuan
CVE-2026-34449
SiYuan is a personal knowledge management system. Prior to version 3.6.2, a malicious website can achieve Remote Code Execution (RCE) on any desktop running SiYuan by exploiting the permissive CORS policy (Access-Control-Allow-Origin: * + Access-Control-Allow-Private-Network: true) to inject a JavaScript snippet via the API. The injected snippet executes in Electron's Node.js context with full OS access the next time the user opens SiYuan's UI. No user interaction is required beyond visiting the malicious website while SiYuan is running. This issue has been patched in version 3.6.2.
EPSS: 0.005 (40.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.6 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H.
Affected products
- B3log Siyuan
- Siyuan-note Siyuan — versions < 3.6.2
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-34449?
- CVE-2026-34449 is a critical-severity vulnerability in B3log Siyuan, classified under Permissive Cross-domain Policy with Untrusted Domains. CVSS score: 9.6/10. Published 2026-03-31.
- How severe is CVE-2026-34449?
- Critical severity. CVSS v3 base score is 9.6 out of 10.