What is CVE-2026-40322?

CVE-2026-40322 is a critical-severity vulnerability in B3log Siyuan, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2026-04-16.

How severe is CVE-2026-40322?

Critical severity. CVSS v3 base score is 9.0 out of 10.

RCE in B3log Siyuan

CVE-2026-40322

SiYuan is an open-source personal knowledge management system. In versions 3.6.3 and below, Mermaid diagrams are rendered with securityLevel set to "loose", and the resulting SVG is injected into the DOM via innerHTML. This allows attacker…

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.003 (22.7th percentile) — read the EPSS interpretation.

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.

Affected products

B3log Siyuan
Siyuan-note Siyuan — versions < 3.6.4

Weakness classification (CWE)

References

security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)
security-advisories@github.com (x_refsource_MISC, Release Notes)

Frequently asked questions

What is CVE-2026-40322?: CVE-2026-40322 is a critical-severity vulnerability in B3log Siyuan, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2026-04-16.
How severe is CVE-2026-40322?: Critical severity. CVSS v3 base score is 9.0 out of 10.