# CVE-2026-23850: SiYuan vulnerable to arbitrary file read

> An attacker can read arbitrary files from the server via unrestricted HTML rendering in the markdown feature of SiYuan.

- **Severity:** High 7.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Jan 2026
- **Updated:** 20 Jan 2026
- **Also known as:** GHSA-cv54-7wv7-qxcw, GO-2026-4347

## What is CVE-2026-23850?

CVE-2026-23850 is a high-severity path traversal vulnerability in B3log Siyuan, published on 19 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

SiYuan is a personal knowledge management system. In versions prior to 3.5.4, the markdown feature allows unrestricted server side html-rendering which allows arbitrary file read (LFD). Version 3.5.4 fixes the issue.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-23850?

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 | 0.0.0-20260118092326-b2274baba2e1 |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260118092326-b2274baba2e1 |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260118092326-b2274baba2e1 |

Products: B3log Siyuan.

## How do I fix CVE-2026-23850?

Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260118092326-b2274baba2e1 or later.

## Is CVE-2026-23850 being exploited?

There is no known exploitation of CVE-2026-23850 in the wild and no public exploit code.

## 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-2026-23850 and fix it if it is affected.

What it is: CVE-2026-23850 is a high-severity path traversal vulnerability in B3log Siyuan, published on 19 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-23850 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260118092326-b2274baba2e1
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260118092326-b2274baba2e1
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260118092326-b2274baba2e1

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-2026-23850/ (Markdown: https://insights.sbomify.com/CVE-2026-23850/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23850
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23850
- OSV: https://osv.dev/vulnerability/CVE-2026-23850

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23850/
Summaries are generated and may contain mistakes; the official description above is the record.