SiYuan: Reflected XSS via SVG namespace prefix bypass in SanitizeSVG ( getDynamicIcon, unauthenticated )

MITRE NVD CVE.ORG Print: PDF PDF

Summary

CVECVE-2026-34605
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-03-31 22:16:22 UTC
Updated2026-04-01 14:23:37 UTC
DescriptionSiYuan is a personal knowledge management system. From version 3.6.0 to before version 3.6.2, the SanitizeSVG function introduced in version 3.6.0 to fix XSS in the unauthenticated /api/icon/getDynamicIcon endpoint can be bypassed by using namespace-prefixed element names such as <x:script xmlns:x="http://www.w3.org/2000/svg">. The Go HTML5 parser records the element's tag as "x:script" rather than "script", so the tag check passes it through. The SVG is served with Content-Type: image/svg+xml and no Content Security Policy; when a browser opens the response directly, its XML parser resolves the prefix to the SVG namespace and executes the embedded script. This issue has been patched in version 3.6.2.

Risk And Classification

Primary CVSS: v4.0 8.6 HIGH from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.000150000 probability, percentile 0.026930000 (date 2026-04-01)

Problem Types: CWE-79 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.6HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED8.6HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
Active
Confidentiality
High
Integrity
High
Availability
Low
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Siyuan-note Siyuan affected >= 3.6.0, < 3.6.2 Not specified

References

ReferenceSourceLinkTags
github.com/siyuan-note/siyuan/issues/17246 [email protected] github.com
github.com/siyuan-note/siyuan/releases/tag/v3.6.2 [email protected] github.com
github.com/siyuan-note/siyuan/security/advisories/GHSA-73g7-86qr-jrg3 [email protected] github.com
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