SiYuan - Path Traversal (CVE-2026-33476)
Description
SiYuan is a personal knowledge management system. Prior to version 3.6.2, the SiYuan kernel exposes an unauthenticated file-serving endpoint under /appearance/*filepath. Due to improper path sanitization, attackers can perform directory traversal and read arbitrary files accessible to the server process. Authentication checks explicitly exclude this endpoint, allowing exploitation without valid credentials. Version 3.6.2 fixes this issue.
psychologyCrowdSec Analysis
CVE-2026-33476 is a path traversal vulnerability in SiYuan prior to version 3.6.2, where an unauthenticated file-serving endpoint fails to properly sanitize file paths. This flaw allows remote attackers to read arbitrary files on the server without authentication, potentially exposing sensitive information and system data. The vulnerability is addressed in version 3.6.2.
CrowdSec has been tracking this vulnerability and its exploits since 24th of June 2026.
CrowdSec network data shows that most actors exploiting CVE-2026-33476 rely on broad, untargeted scans with minimal filtering. The activity is largely automated and opportunistic in nature. CrowdSec network telemetry also shows that exploitation of CVE-2026-33476 has significantly declined over the past week. Attack volumes are well below the long-term average, suggesting attackers are rapidly losing interest. The vulnerability appears to be falling out of active use across most threat landscapes.
Attackers exploit the unauthenticated /appearance/ endpoint by sending requests with path traversal sequences (e.g., /appearance/langs/../../) to access sensitive files on the server. This allows arbitrary file read without authentication on vulnerable SiYuan instances.
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| Event | Date |
|---|---|
| CVE Published | 2026-03-20 |
| Rule Released | 2026-06-24 |
| CrowdSec First Seen | 2026-07-20 |
Related Weaknesses
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
The product allows user input to control or influence paths or file names that are used in filesystem operations.