Remote code execution via unrestricted destination path
Published Feb 4, 2026 · Updated Feb 4, 2026
Path traversal in SiYuan before 3.5.5 allows remote authenticated users to write files outside the workspace via the copyFile API. The copyFile function passes the unvalidated dest value directly to filelock.Copy, permitting an absolute path outside the workspace. Successful abuse requires an administrator API token and a writable destination; startup files, SSH keys, or scheduled-task files enable code execution as the SiYuan process.
Summary
What happened
Path traversal in SiYuan before 3.5.5 allows remote authenticated users to write files outside the workspace via the copyFile API. The copyFile function passes the unvalidated dest value directly to filelock.Copy, permitting an absolute path outside the workspace. Successful abuse requires an administrator API token and a writable destination; startup files, SSH keys, or scheduled-task files enable code execution as the SiYuan process.
The record
- CVE
- CVE-2026-25539
- Published
- Feb 4, 2026
- Updated
- Feb 4, 2026
- Vendor
- SiYuan Note
- Product
- SiYuan
- Classifications
- CWE-22, T1190
- Attack vector
- network
- Privileges
- admin
Timeline
How it unfolded
- Feb 4, 2026CVE publishedPublication date reported by the CVE source.
- Feb 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 3.5.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GHSA-c4jr-5q7w-f6r9 proof of conceptfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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