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CVE-2026-34449

B3log Siyuan remote code execution

9.6 CRITICALPublic exploitEPSS 0.80%
  1. Published31 Mar 2026

Description

SiYuan is a personal knowledge management system. Prior to version 3.6.2, a malicious website can achieve Remote Code Execution (RCE) on any desktop running SiYuan by exploiting the permissive CORS policy (Access-Control-Allow-Origin: * + Access-Control-Allow-Private-Network: true) to inject a JavaScript snippet via the API. The injected snippet executes in Electron's Node.js context with full OS access the next time the user opens SiYuan's UI. No user interaction is required beyond visiting the malicious website while SiYuan is running. This issue has been patched in version 3.6.2.

CVSS 3.1 breakdown

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

Affected products

B3log Siyuan< 3.6.2

Remediation

Fixed in
B3log Siyuan≥ 3.6.2

References

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Frequently asked

Is CVE-2026-34449 being actively exploited?

CVE-2026-34449 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.80%.

How severe is CVE-2026-34449?

CVE-2026-34449 has a CVSS 3.1 base score of 9.6, rated critical. EPSS estimates a 0.80% probability of exploitation.

Which products are affected by CVE-2026-34449?

Affected products include B3log Siyuan.

How do I fix CVE-2026-34449?

Upgrade affected software to a fixed version, for example B3log Siyuan 3.6.2 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-34449 against the real software inventory on every managed device, every day. 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.