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.

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: * +…

EPSS: 0.005 (39.6th 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)

CWE-942 — Permissive Cross-domain Policy with Untrusted Domains

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.