CVE-2026-34605

MEDIUM NUCLEI

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

Title source: cna
STIX 2.1

Exploitation Summary

CVE-2026-34605 has a Nuclei detection template available — see the Nuclei card below for the Shodan/FOFA recon queries.

Description

SiYuan 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.

Nuclei Templates (1)

SiYuan Note - Cross-Site Scripting
MEDIUMVERIFIEDby ritikchaddha
Shodan: http.favicon.hash:-1450125239

References (3)

Core 3
Core References
X_Refsource_Misc x_refsource_misc
https://github.com/siyuan-note/siyuan/issues/17246

Scores

CVSS v3 6.1
EPSS 0.0016
EPSS Percentile 37.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact total

Details

CWE
CWE-79
Status published
Products (3)
b3log/siyuan 3.6.0 - 3.6.2
siyuan-note/siyuan 0 - 0.0.0-20260330031106-f09953afc57aGo
siyuan-note/siyuan >= 3.6.0, < 3.6.2
Published Mar 31, 2026
Tracked Since Apr 01, 2026