CVE-2026-40259 SiYuan: Publish Reader Can Arbitrarily Delete Attribute View Files via removeUnusedAttributeView API
An authenticated reader can arbitrarily delete attribute view files in SiYuan, causing data loss and rendering breakage.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-40259?
CVE-2026-40259 is a high-severity missing authorization vulnerability in B3log Siyuan, published on 16 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
SiYuan is an open-source personal knowledge management system. In versions 3.6.3 and below, the /api/av/removeUnusedAttributeView endpoint is protected only by generic authentication that accepts publish-service RoleReader tokens. The handler passes a caller-controlled id directly to a model function that unconditionally deletes the corresponding attribute view file from the workspace without verifying that the caller has write privileges or that the target attribute view is actually unused. An authenticated publish-service reader can permanently delete arbitrary attribute view definitions by extracting publicly exposed data-av-id values from published content, causing breakage of database views and workspace rendering until manually restored. This issue has been fixed in version 3.6.4.
Weakness: CWE-285
Which versions are affected by CVE-2026-40259?
3 open source packages ship an affected version, including github.com/siyuan-note/siyuan/kernel. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260407035653-2f416e5253f1 |
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260407035653-2f416e5253f1 |
github.com/siyuan-note/siyuan/kernel Go | All versions | 0.0.0-20260407035653-2f416e5253f1 |
Products include B3log Siyuan.
How do I fix CVE-2026-40259?
Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260407035653-2f416e5253f1 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-40259 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40259 exists.
Other vulnerabilities in B3log Siyuan
- CVE-2026-32938 SiYuan has an Arbitrary File Read in its Desktop Publish Service
- CVE-2026-33669 SiYuan has Arbitrary Document Reading within the Publishing Service
- CVE-2026-33670 SiYuan has directory traversal within its publishing service
- CVE-2026-32767 SiYuan: Authorization Bypass Allows Arbitrary SQL Execution via Search API
- CVE-2024-53504 SQL injection in n/a
Sources
Also known as GHSA-7m5h-w69j-qggg, GO-2026-5229.