CVE-2026-66395: SiYuan desktop before v3.7.2 contains a reflected cross-site scripting vulnerability in the bazaar plugin read

This month

CRITICAL 9.6

CVE-2026-66395 is a critical-severity flaw (CVSS 9.6) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

SiYuan desktop before v3.7.2 contains a reflected cross-site scripting vulnerability in the bazaar plugin readme handler that allows attackers to execute arbitrary code by crafting a malicious siyuan:// deep link. Attackers can inject HTML payloads via the plugin name parameter that execute with full Node.js access through insertAdjacentHTML rendering in an insecurely configured Electron renderer.

Why this priority

Critical severity
CISA SSVC: public proof of concept

A fixed release or distro patch exists.

Risk facts

CVSS score	9.6 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.6% (top 54%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-07-27
Last modified	2026-10-24

Publisher (CNA): VulnCheck

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-07-27 16:18 UTCPublished CVE record published
2026-10-24 13:10 UTCUpdated Record last modified

Exact fixes by distribution

Fedora 46 · gnome-shell-extension-tiling-assistant · FIXED · 56-1.fc46 · FEDORA-2026-ebf66a5321 · source

sudo dnf upgrade --advisory=FEDORA-2026-ebf66a5321

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: github.com/siyuan-note/siyuan/security/advisories/GHSA-6gx2-8gcr-x83f

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-66395?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-66395 being exploited?

CVE-2026-66395 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-66395 affect?

CVE-2026-66395 affects affected software. Severity is critical (CVSS 9.6). SiYuan desktop before v3.7.2 contains a reflected cross-site scripting vulnerability in the bazaar plugin readme handler that allows attackers to execute arbitrary code by crafting a malicious siyuan:// deep link. Attackers can inject HTML

How urgent is CVE-2026-66395?

Priority 48/100. Critical severity; CISA SSVC: public proof of concept

Software pages

Node.js vulnerabilities · Electron vulnerabilities

References

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