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CVE-2026-34605

HIGHCVSS 8.6/10EPSS 0.47%

Last modified

CVE-2026-34605 is a high-severity vulnerability rated 8.6/10 on the CVSS scale. 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">. EPSS estimates a 0.47% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS 4.0
8.6/10

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 Probability
0.47%

37.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
B3logSiyuan>= 3.6.0, < 3.6.2

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-34605?
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.
How severe is CVE-2026-34605?
CVE-2026-34605 has a CVSS score of 8.6/10 (HIGH severity). The EPSS model estimates a 0.47% probability of exploitation in the next 30 days.
How do I fix CVE-2026-34605?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-34605?

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Source: NVD / NIST