What’s Vulnerable › Vulnerabilities

CVE-2026-25539: SiYuan has Arbitrary File Write via /api/file/copyFile leading to RCE

• Severity: high (CVSS 7.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.1% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-02-04 · updated 2026-06-17
• Weakness: CWE-22

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.

Affected products

• siyuan-note siyuan: through 3.5.3

References

• https://github.com/siyuan-note/siyuan/commit/d7f790755edf8c78d2b4176171e5a0cdcd720feb
• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-c4jr-5q7w-f6r9
• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-c4jr-5q7w-f6r9

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