CVE-2026-87809 Siyuan before v3.8.2 Information Disclosure via Export Preview
High 7.1
Published
Updated
Check this codebase for CVE-2026-87809 and fix it if it is affected.
What it is: CVE-2026-87809 is a high-severity vulnerability in siyuan-note siyuan, published on 9 Sep 2026.
Exploitation: There is no known exploitation of CVE-2026-87809 in the wild and no public exploit code.
Affected product: siyuan-note siyuan. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-87809/ (Markdown: https://insights.sbomify.com/CVE-2026-87809/index.md)
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-87809?
CVE-2026-87809 is a high-severity vulnerability in siyuan-note siyuan, published on 9 Sep 2026.
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.
Weakness: CWE-639
Which versions are affected by CVE-2026-87809?
How do I fix CVE-2026-87809?
No fix has been published for CVE-2026-87809 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-87809 being exploited?
There is no known exploitation of CVE-2026-87809 in the wild and no public exploit code.
Sources
Also known as GHSA-8wx4-fvqw-f5f8, GHSA-ghrq-8gf7-vmrq.