SiYuan - Path Traversal (CVE-2026-54066)
Description
SiYuan (versions <= 3.6.5) is affected by an unauthenticated path traversal vulnerability in its /assets/ file-serving route. The endpoint fails to properly sanitize double URL-encoded traversal sequences (e.g. %252e%252e/), allowing an unauthenticated attacker to escape the assets directory and read arbitrary files accessible to the server process. Instances running in publish mode (default port 6808) are particularly exposed, where retrieving conf/conf.json leaks sensitive data such as API tokens and authentication hashes.
psychologyCrowdSec Analysis
CVE-2026-54066 is a newly identified vulnerability, but specific details regarding its nature, affected components, and potential impact have not yet been disclosed. As information becomes available, organizations should monitor official advisories to assess risk and determine appropriate mitigation steps.
CrowdSec has been tracking this vulnerability and its exploits since 24th of June 2026.
According to CrowdSec data, while opportunistic exploitation dominates, a portion of threat actors trying to exploit CVE-2026-54066 apply basic targeting methods such as port or service detection. This indicates emerging patterns of selective targeting. Data from the CrowdSec community also indicates a gradual decrease in attacks targeting CVE-2026-54066. While still present in the wild, exploitation levels have dropped noticeably week-over-week. This may signal that the vulnerability is becoming less relevant or that defenses are improving fast enough for attackers to lose interest.
Attackers exploit double URL-encoded path traversal sequences such as /assets/%252e%252e/%252e%252e/ to access sensitive files like conf/conf.json on SiYuan servers running in publish mode (port 6808).
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| Event | Date |
|---|---|
| CVE Published | 2026-06-19 |
| Rule Released | 2026-06-24 |
| CrowdSec First Seen | 2026-06-25 |