# CVE-2026-87808: SiYuan before v3.8.2 Read-Only Boundary Bypass via fullTextSearchBlock

> Authenticated administrators can bypass read-only mode restrictions to execute arbitrary SQL queries and read database contents in SiYuan.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/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:** 9 Sep 2026
- **Updated:** 9 Sep 2026
- **Also known as:** GHSA-4qwm-3p58-vh67, GHSA-hfpm-rwr4-jjg8

## What is CVE-2026-87808?

CVE-2026-87808 is a high-severity missing authorization vulnerability in siyuan-note siyuan, published on 9 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

SiYuan versions <= 3.8.1 contain an incomplete fix for CVE-2026-32767 (GHSA-j7wh-x834-p3r7). The prior fix (commit d5e2d0bc) added an administrator check for SQL mode (method=2) in POST /api/search/fullTextSearchBlock, but the endpoint still does not enforce the application's read-only boundary: for method=2 it forwards caller-supplied SQL to the blocks database query path without calling model.CheckReadonly or CheckReadonlyStatementInBox. As a result, when a workspace runs in read-only mode (--readonly=true), an authenticated administrator can submit arbitrary SQL through /api/search/fullTextSearchBlock and obtain raw read access to the blocks database, even though the dedicated /api/query/sql endpoint is blocked in that mode. Fixed in v3.8.2.

Weakness: CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-87808?


## How do I fix CVE-2026-87808?

No fix has been published for CVE-2026-87808 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-87808 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-87808 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-87808 and fix it if it is affected.

What it is: CVE-2026-87808 is a high-severity missing authorization vulnerability in siyuan-note siyuan, published on 9 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-2026-87808 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-2026-87808/ (Markdown: https://insights.sbomify.com/CVE-2026-87808/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-87808
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-87808
- OSV: https://osv.dev/vulnerability/CVE-2026-87808

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-87808/
Summaries are generated and may contain mistakes; the official description above is the record.