# CVE-2026-34449: SiYuan: Cross-Origin RCE via Permissive CORS Policy and JavaScript Snippet Injection

> Attackers can achieve remote code execution on SiYuan desktop via JavaScript injection exploiting permissive CORS policies.

- **Severity:** Critical 9.7 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 31 Mar 2026
- **Updated:** 1 Apr 2026
- **Also known as:** GHSA-68p4-j234-43mv, GO-2026-5171

## What is CVE-2026-34449?

CVE-2026-34449 is a critical code injection vulnerability in B3log Siyuan, published on 31 Mar 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 is a personal knowledge management system. Prior to version 3.6.2, a malicious website can achieve Remote Code Execution (RCE) on any desktop running SiYuan by exploiting the permissive CORS policy (Access-Control-Allow-Origin: * + Access-Control-Allow-Private-Network: true) to inject a JavaScript snippet via the API. The injected snippet executes in Electron's Node.js context with full OS access the next time the user opens SiYuan's UI. No user interaction is required beyond visiting the malicious website while SiYuan is running. This issue has been patched in version 3.6.2.

Weakness: CWE-942 (Permissive Cross-domain Security Policy with Untrusted Domains)

## Which versions are affected by CVE-2026-34449?

3 open source packages ship an affected version, including github.com/siyuan-note/siyuan/kernel. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | None |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 3.6.2 |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 3.6.2 |

Products: B3log Siyuan.

## How do I fix CVE-2026-34449?

Upgrade github.com/siyuan-note/siyuan/kernel to 3.6.2 or later.

## Is CVE-2026-34449 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34449 exists.

## Other vulnerabilities in B3log Siyuan

- [CVE-2026-32938](https://insights.sbomify.com/CVE-2026-32938/): SiYuan has an Arbitrary File Read in its Desktop Publish Service (critical 9.9)
- [CVE-2026-33669](https://insights.sbomify.com/CVE-2026-33669/): SiYuan has Arbitrary Document Reading within the Publishing Service (critical 9.8)
- [CVE-2026-33670](https://insights.sbomify.com/CVE-2026-33670/): SiYuan has directory traversal within its publishing service (critical 9.8)
- [CVE-2026-32767](https://insights.sbomify.com/CVE-2026-32767/): SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API (critical 9.8)
- [CVE-2024-53504](https://insights.sbomify.com/CVE-2024-53504/): SQL injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34449 and fix it if it is affected.

What it is: CVE-2026-34449 is a critical code injection vulnerability in B3log Siyuan, published on 31 Mar 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34449 exists.

Affected packages and fixed versions:
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; no fix listed
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 3.6.2
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 3.6.2

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-2026-34449/ (Markdown: https://insights.sbomify.com/CVE-2026-34449/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34449
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34449
- OSV: https://osv.dev/vulnerability/CVE-2026-34449

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34449/
Summaries are generated and may contain mistakes; the official description above is the record.