# CVE-2026-93921: SiYuan through 3.8.4 Access Control Bypass via Dynamic Icon Endpoint

> Attackers with read-only tokens can bypass access controls to read restricted document metadata via the dynamic icon endpoint.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Sep 2026
- **Updated:** 21 Sep 2026
- **Also known as:** GHSA-j5v6-qhh5-48r7, GHSA-whcx-xxqh-c838

## What is CVE-2026-93921?

CVE-2026-93921 is a medium-severity missing authorization vulnerability in siyuan-note siyuan, published on 18 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

SiYuan versions through 3.8.4 fail to enforce publish access control in the getDynamicIcon endpoint, allowing read-only token holders to access document metadata. Attackers can call the endpoint with type=8 and crafted content to read block titles, names, aliases, and hierarchical paths of restricted documents via template injection.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-93921?


## How do I fix CVE-2026-93921?

No fix has been published for CVE-2026-93921 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-93921 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-93921 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93921 and fix it if it is affected.

What it is: CVE-2026-93921 is a medium-severity missing authorization vulnerability in siyuan-note siyuan, published on 18 Sep 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-2026-93921 exists.

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-2026-93921/ (Markdown: https://insights.sbomify.com/CVE-2026-93921/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93921
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93921
- OSV: https://osv.dev/vulnerability/CVE-2026-93921

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93921/
Summaries are generated and may contain mistakes; the official description above is the record.