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CVE-2026-32940

B3log Siyuan cross-site scripting (XSS)

9.3 CRITICALPublic exploitEPSS 0.46%
  1. Published20 Mar 2026

Description

SiYuan is a personal knowledge management system. In versions 3.6.0 and below, SanitizeSVG has an incomplete blocklist — it blocks data:text/html and data:image/svg+xml in href attributes but misses data:text/xml and data:application/xml, both of which can render SVG with JavaScript execution. The unauthenticated /api/icon/getDynamicIcon endpoint serves user-controlled input (via the content parameter) directly into SVG markup using fmt.Sprintf with no escaping, served as Content-Type: image/svg+xml. This creates a click-through XSS: a victim navigates to a crafted URL, sees an SVG with an injected link, and clicking it triggers JavaScript via the bypassed MIME types. The attack requires direct navigation to the endpoint or <object>/<embed> embedding, since <img> tag rendering in the frontend doesn't allow interactive links. This issue has been fixed in version 3.6.1.

CVSS 3.1 breakdown

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

Affected products

B3log Siyuan< 3.6.1

Remediation

Fixed in
B3log Siyuan≥ 3.6.1

References

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Frequently asked

Is CVE-2026-32940 being actively exploited?

CVE-2026-32940 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.46%.

How severe is CVE-2026-32940?

CVE-2026-32940 has a CVSS 3.1 base score of 9.3, rated critical. EPSS estimates a 0.46% probability of exploitation.

Which products are affected by CVE-2026-32940?

Affected products include B3log Siyuan.

How do I fix CVE-2026-32940?

Upgrade affected software to a fixed version, for example B3log Siyuan 3.6.1 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-32940 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.