vulnerability / NVI-00014027 / Revision 1
SiYuan: Stored and reflected XSS in SiYuan through an SVG sanitizer bypass
GitHub lists this reviewed advisory for github.com/siyuan-note/siyuan/kernel. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
8.7 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/siyuan-note/siyuan/kernel
source listed< 0.0.0-20260714095344-f08dee71ba8e
### Summary SiYuan cleans user supplied SVG with `util.SanitizeSVG` before it serves the file inline as `image/svg+xml`. This cleaner is the guard behind the `Editor.AllowSVGScript` setting, which is off by default, so a `` inside an SVG is meant to be removed. The cleaner reads the input as HTML, but the browser reads the served file as XML (SVG). Because the two parsers treat some tags differently, a `` can be hidden so the cleaner never removes it. The cleaned file still holds a working script. When a browser opens that file as an SVG document, the script runs in the app origin. There is no Content Security Policy in the product to stop it. The same bug can be reached in two ways. Both share one root cause (the cleaner), so one fix in the cleaner closes both: * Reflected, through a single link: `GET /api/icon/getDynamicIcon` * Stored, through a planted `.svg` asset: `GET /assets/.svg` I confirmed this on a live SiYuan 3.7.2 kernel. ## Root cause `util.SanitizeSVG` (`kernel/util/misc.go:319`) parses the string with an HTML parser, walks the element nodes to drop ``, ``, ``, event handler attributes and so on, then renders
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-99rq-75j6-5j9f ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
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