# CVE-2026-54067: SiYuan: Stored XSS to RCE via CSS-snippet <style> breakout in renderSnippet()

> Stored XSS in SiYuan allows remote code execution on Electron desktops via CSS snippet injection, bypassing JavaScript security settings.

- **Severity:** Critical 9.9 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Jun 2026
- **Updated:** 25 Jun 2026
- **Also known as:** GHSA-mvjr-vv3c-w4qv, GO-2026-5963

## What is CVE-2026-54067?

CVE-2026-54067 is a critical cross-site scripting vulnerability in siyuan-note siyuan, published on 24 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, CSS snippet body containing </style> breaks out of its surrounding <style> tag when renderSnippet() interpolates it via insertAdjacentHTML. A payload like runs arbitrary JavaScript in the renderer. On Electron desktop builds the renderer runs with nodeIntegration:true, so require('child_process') is reachable from the injected handler and the XSS chains to host RCE. Snippets sync via the workspace repository, so an attacker with write access to any synced workspace plants the payload once and it fires on every device that pulls. The bug also bypasses the user's enabledCSS / enabledJS separation. A user who turned enabledJS off was making a deliberate call not to run untrusted JavaScript; the CSS path runs it anyway. This vulnerability is fixed in 3.7.0.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-1188 (Initialization of a Resource with an Insecure Default)

## Which versions are affected by CVE-2026-54067?

3 open source packages ship an affected version, including github.com/siyuan-note/siyuan/kernel.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260628153353-2d5d72223df4 |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260628153353-2d5d72223df4 |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260628153353-2d5d72223df4 |

## How do I fix CVE-2026-54067?

Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260628153353-2d5d72223df4 or later.

## Is CVE-2026-54067 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54067 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54067 and fix it if it is affected.

What it is: CVE-2026-54067 is a critical cross-site scripting vulnerability in siyuan-note siyuan, published on 24 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54067 exists.

Affected packages and fixed versions:
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260628153353-2d5d72223df4
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260628153353-2d5d72223df4
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260628153353-2d5d72223df4

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-2026-54067/ (Markdown: https://insights.sbomify.com/CVE-2026-54067/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54067
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54067
- OSV: https://osv.dev/vulnerability/CVE-2026-54067

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54067/
Summaries are generated and may contain mistakes; the official description above is the record.