CVE-2026-25539 | THREATINT

Description

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 lead to Remote Code Execution (RCE) by writing to sensitive locations such as cron jobs, SSH authorized_keys, or shell configuration files. This issue has been patched in version 3.5.5.

PUBLISHED Reserved 2026-02-02 | Published 2026-02-04 | Updated 2026-02-05 | Assigner GitHub_M

CRITICAL: 9.1CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Problem types

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Product status

< 3.5.5

affected

References

github.com/...siyuan/security/advisories/GHSA-c4jr-5q7w-f6r9 exploit

github.com/...siyuan/security/advisories/GHSA-c4jr-5q7w-f6r9

github.com/...ommit/d7f790755edf8c78d2b4176171e5a0cdcd720feb

cve.org (CVE-2026-25539)

nvd.nist.gov (CVE-2026-25539)

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