CVE-2026-25539

CRITICAL

9.1

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.

CVE Details

CVSS v3.1 Score9.1

SeverityCRITICAL

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

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredHIGH

User InteractionNONE

Published2/4/2026

Last Modified2/11/2026

Sourcenvd

Honeypot Sightings0

Affected Products

b3log:siyuan

Weaknesses (CWE)

CWE-22

References

https://github.com/siyuan-note/siyuan/commit/d7f790755edf8c78d2b4176171e5a0cdcd720feb(security-advisories@github.com)

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-c4jr-5q7w-f6r9(security-advisories@github.com)

https://github.com/siyuan-note/siyuan/security/advisories/GHSA-c4jr-5q7w-f6r9(134c704f-9b21-4f2e-91b3-4a467353bcc0)

IOC Correlations

No correlations recorded

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