CVE-2026-25539 json
SiYuan has Arbitrary File Write via /api/file/copyFile leading to RCE
published 2026-01-29 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-5331 , GHSA-c4jr-5q7w-f6r9 , GO-2026-4387
- cvss
- 9.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.1%
- EPSS 1.1% chance of exploitation in 30 days, percentile 66%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 9 mo ago
Exploit prediction
1.10% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/siyuan-note/siyuan/security/advisories/GHSA-c4jr-5q7w-f6r9 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H |
| GitHub | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H |
| NVD | 3.1 | 7.2 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/siyuan-note/siyuan/kernel | <=0.0.0-20260126094835-d5d10dd41b0c all versions |
no fix listed |
Affected products
- siyuan-note siyuan
Classification
- Weakness
-
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory
References
-
github.com
/siyuan-note/siyuan/commit/d7f790755edf8c78d2b4176171e5a0cdcd720feb
web, patch
-
github.com
/siyuan-note/siyuan/security/advisories/GHSA-c4jr-5q7w-f6r9
exploit, web, vendor-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-25539
advisory
-
github.com
/siyuan-note/siyuan
package
Sources
- CVE List CVE-2026-25539
- GitHub Advisory GHSA-c4jr-5q7w-f6r9
- NVD CVE-2026-25539
- OSV GO-2026-4387
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.