What is CVE-2026-33067?

CVE-2026-33067 is a critical-severity vulnerability in B3log Siyuan, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2026-03-20.

How severe is CVE-2026-33067?

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

Is CVE-2026-33067 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

XSS in B3log Siyuan

CVE-2026-33067

SiYuan is a personal knowledge management system. Versions 3.6.0 and below render package metadata fields (displayName, description) using template literals without HTML escaping. A malicious package author can inject arbitrary HTML/JavaScript into these fields, which executes automatically when any user browses the Bazaar page. Because SiYuan's Electron configuration enables nodeIntegration: true with contextIsolation: false, this XSS escalates directly to full Remote Code Execution on the victim's operating system — with zero user interaction beyond opening the marketplace tab. This issue has been fixed in version 3.6.1.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.005 (42.7th 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 < 3.6.1

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

Lopseg/cve-2026-33067

References

security-advisories@github.com (x_refsource_CONFIRM, Exploit, Mitigation, Vendor Advisory)

Frequently asked questions

What is CVE-2026-33067?: CVE-2026-33067 is a critical-severity vulnerability in B3log Siyuan, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2026-03-20.
How severe is CVE-2026-33067?: Critical severity. CVSS v3 base score is 9.0 out of 10.
Is CVE-2026-33067 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.