SiYuan has a SanitizeSVG bypass via data:text/xml in getDynamicIcon (incomplete fix for CVE-2026-29183)
Description
SiYuan is a personal knowledge management system. In versions 3.6.0 and below, SanitizeSVG has an incomplete blocklist — it blocks data:text/html and data:image/svg+xml in href attributes but misses data:text/xml and data:application/xml, both of which can render SVG with JavaScript execution. The unauthenticated /api/icon/getDynamicIcon endpoint serves user-controlled input (via the content parameter) directly into SVG markup using fmt.Sprintf with no escaping, served as Content-Type: image/svg+xml. This creates a click-through XSS: a victim navigates to a crafted URL, sees an SVG with an injected link, and clicking it triggers JavaScript via the bypassed MIME types. The attack requires direct navigation to the endpoint or <object>/<embed> embedding, since <img> tag rendering in the frontend doesn't allow interactive links. This issue has been fixed in version 3.6.1.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
github.com/siyuan-note/siyuanGo | <= 0.0.0-20260313024916-fd6526133bb3 | — |
Affected products
1- Range: < 3.6.1
Patches
1d01d561875d4:lock: https://github.com/siyuan-note/siyuan/security/advisories/GHSA-4mx9-3c2h-hwhg
1 file changed · +6 −2
kernel/util/misc.go+6 −2 modified@@ -285,9 +285,13 @@ func SanitizeSVG(svgInput string) string { if strings.HasPrefix(val, "javascript:") { continue } - // 对 data: 做保守处理，删除包含可执行内容的 data:text/html 或 data:image/svg+xml + // 对 data: 做保守处理，只允许常见安全的图片格式（png/jpeg/gif/webp） if strings.HasPrefix(val, "data:") { - if strings.Contains(val, "text/html") || strings.Contains(val, "image/svg+xml") || strings.Contains(val, "application/xhtml+xml") { + safe := strings.HasPrefix(val, "data:image/png") || + strings.HasPrefix(val, "data:image/jpeg") || + strings.HasPrefix(val, "data:image/gif") || + strings.HasPrefix(val, "data:image/webp") + if !safe { continue } }
Vulnerability mechanics
Generated by null/stub on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
6- github.com/advisories/GHSA-4mx9-3c2h-hwhgghsaADVISORY
- github.com/advisories/GHSA-6865-qjcf-286fghsax_refsource_MISCADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-32940ghsaADVISORY
- github.com/siyuan-note/siyuan/commit/d01d561875d4f744e9f6232f1d4831e3642b8696ghsax_refsource_MISCWEB
- github.com/siyuan-note/siyuan/releases/tag/v3.6.1ghsax_refsource_MISCWEB
- github.com/siyuan-note/siyuan/security/advisories/GHSA-4mx9-3c2h-hwhgghsax_refsource_CONFIRMWEB
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