# CVE-2026-87814: SiYuan before v3.8.2 Stored XSS via Asset Preview

> Attackers can execute JavaScript in SiYuan via stored XSS in asset previews, enabling API requests and workspace manipulation.

- **Severity:** High 8.4 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 9 Sep 2026
- **Updated:** 18 Sep 2026
- **Also known as:** GHSA-64gp-333q-mq6j, GHSA-gxwj-6x5p-v77c

## What is CVE-2026-87814?

CVE-2026-87814 is a high-severity cross-site scripting vulnerability in siyuan-note siyuan, published on 9 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

SiYuan before v3.8.2 contains a stored cross-site scripting vulnerability in the search asset preview feature that fails to escape indexed asset content before inserting it into the DOM using innerHTML. Attackers who can place crafted text assets in a workspace can execute JavaScript in the SiYuan origin when victims preview the assets, enabling authenticated API requests and workspace manipulation.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-87814?


## How do I fix CVE-2026-87814?

No fix has been published for CVE-2026-87814 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-87814 being exploited?

There is no known exploitation of CVE-2026-87814 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-87814 and fix it if it is affected.

What it is: CVE-2026-87814 is a high-severity cross-site scripting vulnerability in siyuan-note siyuan, published on 9 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-87814 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-2026-87814/ (Markdown: https://insights.sbomify.com/CVE-2026-87814/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-87814
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-87814
- OSV: https://osv.dev/vulnerability/CVE-2026-87814

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-87814/
Summaries are generated and may contain mistakes; the official description above is the record.