SiYuan vulnerable to reflected XSS via SVG namespace prefix bypass in SanitizeSVG (getDynamicIcon, unauthenticated)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.6 · 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 · score source

EPSS

• CVE-2026-34605: 0.47% estimated exploitation activity in the next 30 days; percentile 40.63 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The SanitizeSVG function introduced in v3.6.0 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. Details The getDynamicIcon route is registered without authentication: For type 8, the content query parameter is inserted directly into an SVG <text element using fmt.Sprintf with no HTML encoding: SanitizeSVG then parses the SVG with github.com/88250/lute/html and removes elements whose lowercased tag name matches a fixed list: The lute HTML parser stores the full qualified name including any namespace prefix in…

Published by the source

1 Apr 2026, 00:30 UTC

Last modified by the source

6 Apr 2026, 16:40 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-73g7-86qr-jrg3

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# Patch Next advisory brief: CVE-2026-34605

Advisory: SiYuan vulnerable to reflected XSS via SVG namespace prefix bypass in SanitizeSVG (getDynamicIcon, unauthenticated)
IDs: CVE-2026-34605, GHSA-73g7-86qr-jrg3
Record: https://patchnext.com/advisories/cve-2026-34605 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/siyuan-note/siyuan/kernel 0.0.0-20260330031106-f09953afc57a. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/siyuan-note/siyuan/kernel: affected < 0.0.0-20260330031106-f09953afc57a; fixed in 0.0.0-20260330031106-f09953afc57a

## Suggested inspection (read-only)
- Go github.com/siyuan-note/siyuan/kernel: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/siyuan-note/siyuan/kernel.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-73g7-86qr-jrg3 (GitHub-reviewed advisory GHSA-73g7-86qr-jrg3 lists affected ranges: Go github.com/siyuan-note/siyuan/kernel >=0 <0.0.0-20260330031106-f09953afc57a)

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