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CVE-2026-33066

MEDIUMCVSS 5.3/10EPSS 0.58%

Last modified

CVE-2026-33066 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. SiYuan is a personal knowledge management system. In versions 3.6.0 and below, the backend renderREADME function uses lute.New() without calling SetSanitize(true), allowing raw HTML embedded in Markdown to pass through unmodified. EPSS estimates a 0.58% chance of exploitation in the next 30 days.

Description

SiYuan is a personal knowledge management system. In versions 3.6.0 and below, the backend renderREADME function uses lute.New() without calling SetSanitize(true), allowing raw HTML embedded in Markdown to pass through unmodified. The frontend then assigns the rendered HTML to innerHTML without any additional sanitization. A malicious package author can embed arbitrary JavaScript in their README that executes when a user clicks to view the package details. Because SiYuan's Electron configuration enables nodeIntegration: true with contextIsolation: false, this XSS escalates directly to full Remote Code Execution. The issue was patched in version 3.6.1.

Metrics

CVSS 3.1
9/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

CVSS 4.0
5.3/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.58%

43.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
B3logSiyuan< 3.6.1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-33066?
SiYuan is a personal knowledge management system. In versions 3.6.0 and below, the backend renderREADME function uses lute.New() without calling SetSanitize(true), allowing raw HTML embedded in Markdown to pass through unmodified. The frontend then assigns the rendered HTML to innerHTML without any additional sanitization. A malicious package author can embed arbitrary JavaScript in their README that executes when a user clicks to view the package details. Because SiYuan's Electron configuration enables nodeIntegration: true with contextIsolation: false, this XSS escalates directly to full Remote Code Execution. The issue was patched in version 3.6.1.
How severe is CVE-2026-33066?
CVE-2026-33066 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.58% probability of exploitation in the next 30 days.
How do I fix CVE-2026-33066?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-33066?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST