CVE-2025-21609 — kernel
Fix: siyuan-note/siyuan@d9887aeCVE-2025-21609 is a CWE-459 vulnerability in github.com/siyuan-note/siyuan/kernel. No vendor fix is recorded yet; mitigation options are listed below.
SiYuan has an arbitrary file deletion vulnerability
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-21609.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
github.com/siyuan-note/siyuan/kernelReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
A arbitrary file deletion vulnerability has been identified in the latest version of Siyuan Note. The vulnerability exists in the POST /api/history/getDocHistoryContent endpoint.An attacker can craft a payload to exploit this vulnerability, resulting in the deletion of arbitrary files on the server.
Details
The vulnerability can be reproduced by sending a crafted request to the /api/history/getDocHistoryContent endpoint.
Sending a request to the /api/history/getDocHistoryContent like:
curl "http://127.0.0.1:6806/api/history/getDocHistoryContent" -X POST -H "Content-Type: application/json" -d '{"historyPath":"<abs_filepath_of_a_file>"}'
Replace <abs_filepath_of_a_file> with the absolute file path of the target file you wish to delete.
The historyPath parameter in the payload is processed by the func getDocHistoryContent in api/history.go:133.
In turn, historyPath is passed to the func GetDocHistoryContent located in model/history.go:150 , which is the slink of the vulnerability.
if historyPath exists and does not satisfy the filesys.ParseJSONWithoutFix, then it will be deleted by os.RemoveAll
func GetDocHistoryContent(historyPath, keyword string, highlight bool) (id, rootID, content string, isLargeDoc bool, err error) {
if !gulu.File.IsExist(historyPath) {
logging.LogWarnf("doc history [%s] not exist", historyPath)
return
}
data, err := filelock.ReadFile(historyPath)
if err != nil {
logging.LogErrorf("read file [%s] failed: %s", historyPath, err)
return
}
isLargeDoc = 1024*1024*1 <= len(data)
luteEngine := NewLute()
historyTree, err := filesys.ParseJSONWithoutFix(data, luteEngine.ParseOptions)
if err != nil {
logging.LogErrorf("parse tree from file [%s] failed, remove it", historyPath)
os.RemoveAll(historyPath)
return
}
...
}
PoC
curl "http://127.0.0.1:6806/api/history/getDocHistoryContent" -X POST -H "Content-Type: application/json" -d '{"historyPath":"<abs_filepath_of_a_file>"}'
Impact
arbitrary file deletion vulnerability
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/siyuan-note/siyuan/kernel | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/siyuan-note/siyuan/kernel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of github.com/siyuan-note/siyuan/kernel has shipped for CVE-2025-21609 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-21609 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-21609. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-21609 in your dependencies?
O3 Security finds CVE-2025-21609 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.