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CVE-2026-39846

B3log Siyuan remote code execution

9.0 CRITICALPublic exploitEPSS 0.65%
  1. Published7 Apr 2026

Description

SiYuan is a personal knowledge management system. Prior to 3.6.4, a malicious note synced to another user can trigger remote code execution in the SiYuan Electron desktop client. The root cause is that table caption content is stored without safe escaping and later unescaped into rendered HTML, creating a stored XSS sink. Because the desktop renderer runs with nodeIntegration enabled and contextIsolation disabled, attacker-controlled JavaScript executes with access to Node.js APIs. In practice, an attacker can import a crafted note into a synced workspace, wait for the victim to sync, and achieve code execution when the victim opens the note. This vulnerability is fixed in 3.6.4.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionRequired
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Affected products

B3log Siyuan< 3.6.4

Remediation

Fixed in
B3log Siyuan≥ 3.6.4

References

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Frequently asked

Is CVE-2026-39846 being actively exploited?

CVE-2026-39846 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.65%.

How severe is CVE-2026-39846?

CVE-2026-39846 has a CVSS 3.1 base score of 9.0, rated critical. EPSS estimates a 0.65% probability of exploitation.

Which products are affected by CVE-2026-39846?

Affected products include B3log Siyuan.

How do I fix CVE-2026-39846?

Upgrade affected software to a fixed version, for example B3log Siyuan 3.6.4 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-39846 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.