Vulnerability · Published Sep 9, 2026 · Assigned by VulnCheck

CVE-2026-87809Siyuan before v3.8.2 Information Disclosure via Export Preview

Medium 6.5

In plain English

A medium-severity authorization bypass via user-controlled key in siyuan from siyuan-note. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 29% of all known vulnerabilities).

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.4%top 70.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
siyuan-note	siyuan	0 – before 3.8.2

Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

References

GitHub Security Advisory (GHSA-8wx4-fvqw-f5f8) vendor-advisory
VulnCheck Advisory: Siyuan before v3.8.2 Information Disclosure via Export Preview third-party-advisory