# CVE-2026-87809

## Summary

- **CVE ID:** CVE-2026-87809
- **Severity:** HIGH
- **CVSS Score:** 7.1 (CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-639
- **Published:** Sep 9, 2026
- **Last Modified:** Sep 9, 2026

## Description

Siyuan before v3.8.2 fails to apply publish-access filtering to embedded blocks before rendering in the /api/export/preview and /api/lute/copyStdMarkdown endpoints. Attackers with reader access can retrieve the full rendered content of private, hidden, or publish-disabled blocks by accessing public documents containing embed queries that select those blocks.

## Affected Products

- siyuan-note — siyuan (0)
- siyuan-note — siyuan (3.8.2)

## References

- [CNA](https://github.com/siyuan-note/siyuan/security/advisories/GHSA-8wx4-fvqw-f5f8)
- [CNA](https://www.vulncheck.com/advisories/siyuan-before-3.8.2-information-disclosure-via-export-preview)

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-09._