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.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
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
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.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-87808 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-87808 exists.
Sources
Also known as GHSA-4qwm-3p58-vh67, GHSA-hfpm-rwr4-jjg8.