# CVE-2026-23645: SiYuan Vulnerable to Stored Cross-Site Scripting (XSS) via Unrestricted SVG File Upload

> Attackers can execute arbitrary JavaScript in a victim's session by uploading malicious SVG files to SiYuan, potentially leading to account takeover.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/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:** Yes
- **Published:** 16 Jan 2026
- **Updated:** 16 Jan 2026
- **Also known as:** GHSA-pcjq-j3mq-jv5j, GO-2026-4324

## What is CVE-2026-23645?

CVE-2026-23645 is a medium-severity cross-site scripting vulnerability in B3log Siyuan, published on 16 Jan 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 self-hosted, open source personal knowledge management software. Prior to 3.5.4-dev2, a Stored Cross-Site Scripting (XSS) vulnerability exists in SiYuan Note. The application does not sanitize uploaded SVG files. If a user uploads and views a malicious SVG file (e.g., imported from an untrusted source), arbitrary JavaScript code is executed in the context of their authenticated session. This vulnerability is fixed in 3.5.4-dev2.

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

## Which versions are affected by CVE-2026-23645?

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 | 0.0.0-20260116101155-11115da3d0de |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260116101155-11115da3d0de |
| `github.com/siyuan-note/siyuan/kernel` | Go | All versions | 0.0.0-20260116101155-11115da3d0de |

Products: B3log Siyuan.

## How do I fix CVE-2026-23645?

Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260116101155-11115da3d0de or later.

## Is CVE-2026-23645 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-23645 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-2026-23645 and fix it if it is affected.

What it is: CVE-2026-23645 is a medium-severity cross-site scripting vulnerability in B3log Siyuan, published on 16 Jan 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-2026-23645 exists.

Affected packages and fixed versions:
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260116101155-11115da3d0de
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260116101155-11115da3d0de
- github.com/siyuan-note/siyuan/kernel (Go): affected all versions; fixed in 0.0.0-20260116101155-11115da3d0de

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-2026-23645/ (Markdown: https://insights.sbomify.com/CVE-2026-23645/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23645
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23645
- OSV: https://osv.dev/vulnerability/CVE-2026-23645

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23645/
Summaries are generated and may contain mistakes; the official description above is the record.