# CVE-2026-86712: SiYuan before 3.8.2 Remote Code Execution via Clipboard

> Attackers can execute arbitrary code via malicious clipboard content in SiYuan due to missing sanitization in the paste handler.

- **Severity:** High 8.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 8 Sep 2026
- **Updated:** 10 Sep 2026
- **Also known as:** GHSA-358r-j9r9-9hv6, GHSA-9rr9-pxr4-gcgc

## What is CVE-2026-86712?

CVE-2026-86712 is a high-severity cross-site scripting vulnerability in siyuan-note siyuan, published on 8 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

SiYuan before 3.8.2 trusts the attacker-writable text/siyuan clipboard MIME type and skips sanitization in the paste handler, allowing code execution in the Node-enabled desktop renderer. Attackers can craft malicious web pages that write to the clipboard, and when pasted into SiYuan, injected scripts execute with full Node.js access through the Electron main process.

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

## Which versions are affected by CVE-2026-86712?


## How do I fix CVE-2026-86712?

No fix has been published for CVE-2026-86712 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-86712 being exploited?

There is no known exploitation of CVE-2026-86712 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-86712 and fix it if it is affected.

What it is: CVE-2026-86712 is a high-severity cross-site scripting vulnerability in siyuan-note siyuan, published on 8 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-86712 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-2026-86712/ (Markdown: https://insights.sbomify.com/CVE-2026-86712/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-86712
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-86712
- OSV: https://osv.dev/vulnerability/CVE-2026-86712

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-86712/
Summaries are generated and may contain mistakes; the official description above is the record.