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CVE-2026-29183

B3log Siyuan cross-site scripting (XSS)

9.3 CRITICALPublic exploitEPSS 0.69%
  1. Published6 Mar 2026

Description

SiYuan is a personal knowledge management system. Prior to version 3.5.9, an unauthenticated reflected XSS vulnerability exists in the dynamic icon API endpoint "GET /api/icon/getDynamicIcon" when type=8, attacker-controlled content is embedded into SVG output without escaping. Because the endpoint is unauthenticated and returns image/svg+xml, a crafted URL can inject executable SVG/HTML event handlers (for example onerror) and run JavaScript in the SiYuan web origin. This can be chained to perform authenticated API actions and exfiltrate sensitive data when a logged-in user opens the malicious link. This issue has been patched in version 3.5.9.

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< 3.5.9

Remediation

Fixed in
B3log Siyuan≥ 3.5.9

References

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Frequently asked

Is CVE-2026-29183 being actively exploited?

CVE-2026-29183 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.69%.

How severe is CVE-2026-29183?

CVE-2026-29183 has a CVSS 3.1 base score of 9.3, rated critical. EPSS estimates a 0.69% probability of exploitation.

Which products are affected by CVE-2026-29183?

Affected products include B3log Siyuan.

How do I fix CVE-2026-29183?

Upgrade affected software to a fixed version, for example B3log Siyuan 3.5.9 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-29183 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.