Path Traversal in B3log Siyuan
CVE-2026-25539
SiYuan is a personal knowledge management system. Prior to version 3.5.5, the /api/file/copyFile endpoint does not validate the dest parameter, allowing authenticated users to write files to arbitrary locations on the filesystem. This can…
Vulnerability class: Path Traversal (Directory Traversal)
EPSS: 0.010 (59.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.
Affected products
- B3log Siyuan
- Siyuan-note Siyuan — versions < 3.5.5
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-25539?
- CVE-2026-25539 is a critical-severity vulnerability in B3log Siyuan, classified under Path Traversal. CVSS score: 9.1/10. Published 2026-02-04.
- How severe is CVE-2026-25539?
- Critical severity. CVSS v3 base score is 9.1 out of 10.