CVE-2026-7240
OS Command Injection in Totolink A8000RU CGI Handler Allows Remote Exploit
Publication date: 2026-04-28
Last updated on: 2026-04-28
Assigner: VulDB
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| totolink | a8000ru | 7.1cu.643_b20200521 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-77 | The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component. |
| CWE-78 | The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-7240 is a command injection vulnerability found in the TOTOLINK A8000RU router, version 7.1cu.643_b20200521. It exists in the CGI script cstecgi.cgi, specifically in the function setVpnAccountCfg. The vulnerability arises because a user-supplied parameter named "user" is improperly handled and passed to a system command execution function without proper sanitization.
An attacker can remotely send a specially crafted POST request to the /cgi-bin/cstecgi.cgi endpoint with malicious content in the "user" parameter. This causes the router to execute arbitrary operating system commands, such as creating files or running other commands, which confirms remote command execution capability.
How can this vulnerability impact me? :
This vulnerability allows remote attackers to execute arbitrary operating system commands on the affected router without authentication. This can lead to full compromise of the device, including unauthorized access, data theft, device manipulation, or disruption of network services.
An attacker could use this flaw to gain control over the router, potentially intercepting or redirecting network traffic, installing malware, or using the device as a foothold to attack other systems within the network.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by sending a crafted POST request to the /cgi-bin/cstecgi.cgi endpoint with a malicious payload in the "user" parameter to test for command injection.
For example, a proof of concept uses the command injection payload `ls>./setVpnAccountCfg.txt` in the "user" parameter. If the router is vulnerable, it will execute the command and create a file named setVpnAccountCfg.txt containing the directory listing.
A detection command could be a curl command like:
- curl -X POST -d "user=ls>./setVpnAccountCfg.txt" http://[router-ip]/cgi-bin/cstecgi.cgi
After running this command, checking the router's filesystem for the presence of the file setVpnAccountCfg.txt indicates successful command execution and thus the presence of the vulnerability.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The CVE-2026-7240 vulnerability allows remote attackers to execute arbitrary operating system commands on the TOTOLINK A8000RU router. This can lead to unauthorized access, data manipulation, or disruption of services.
Such unauthorized command execution can compromise the confidentiality, integrity, and availability of data handled by the device, which may result in non-compliance with data protection standards and regulations like GDPR and HIPAA that require safeguarding sensitive information and ensuring system security.
Therefore, exploitation of this vulnerability could lead to violations of these regulations due to potential data breaches or loss of control over protected data.
What immediate steps should I take to mitigate this vulnerability?
To mitigate the CVE-2026-7240 vulnerability in the TOTOLINK A8000RU router, immediate steps include restricting remote access to the affected CGI handler, especially the /cgi-bin/cstecgi.cgi endpoint, to prevent exploitation of the command injection flaw.
Additionally, applying any available firmware updates or patches from the vendor that address this vulnerability is critical.
If patches are not yet available, consider disabling the vulnerable service or CGI functionality temporarily to block remote command execution.
Monitoring network traffic for suspicious POST requests targeting the setVpnAccountCfg function and the 'user' parameter can help detect exploitation attempts.