CVE-2026-40318: SiYuan: Publish Reader Path Traversal Delete via `removeUnusedAttributeView`

Severity: high (CVSS 8.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-16 · updated 2026-06-17
Weakness: CWE-24

Description

SiYuan is an open-source personal knowledge management system. In versions 3.6.3 and prior, the /api/av/removeUnusedAttributeView endpoint constructs a filesystem path using the user-controlled id parameter without validation or path boundary enforcement. An attacker can inject path traversal sequences such as ../ into the id value to escape the intended directory and delete arbitrary .json files on the server, including global configuration files and workspace metadata. This issue has been fixed in version 3.6.4.

Affected products

siyuan-note siyuan: before 3.6.4 — fixed in 3.6.4

How to fix

Upgrade to a fixed version: siyuan-note siyuan 3.6.4. Check the vendor advisory for mitigations.

References

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