mcp-dnstwist OS Command Injection Vulnerability (CVE-2026-7443)

CVE-2026-7443 describes an OS command injection vulnerability affecting BurtTheCoder’s mcp-dnstwist, a tool potentially used for detecting and preventing typosquatting attacks. The vulnerability resides in versions up to 1.0.4. The affected function, fuzz_domain, located in the src/index.ts file of the MCP Interface component, is susceptible to command injection. An attacker can manipulate the Request argument to inject arbitrary OS commands. This is a remotely exploitable vulnerability, meaning an attacker can trigger it over a network connection. Public exploits are available, increasing the risk of widespread exploitation. The vulnerability was reported to the project maintainers, but no response or patch has been released as of this writing.

Attack Chain

1. The attacker identifies a vulnerable instance of mcp-dnstwist running version 1.0.4 or earlier.
2. The attacker crafts a malicious HTTP request targeting the MCP Interface component.
3. The crafted request includes a payload designed to exploit the fuzz_domain function in src/index.ts.
4. The malicious payload manipulates the Request argument, injecting OS commands.
5. The fuzz_domain function, without proper sanitization, executes the injected OS commands.
6. The attacker gains arbitrary code execution on the server hosting mcp-dnstwist.
7. The attacker leverages the initial access to escalate privileges or move laterally within the network.
8. The attacker achieves their final objective, such as data exfiltration or system compromise.

Impact

Successful exploitation of this vulnerability allows a remote attacker to execute arbitrary OS commands on the system hosting mcp-dnstwist. This could lead to complete system compromise, data breaches, or denial-of-service conditions. Given that mcp-dnstwist might be used in security-sensitive environments, a successful attack could have significant impact. The lack of a patch and the availability of public exploits increase the likelihood of exploitation.

Recommendation

• Since no patch is available, immediately discontinue use of mcp-dnstwist versions up to 1.0.4.
• Monitor network traffic for suspicious requests targeting mcp-dnstwist instances by deploying the Sigma rule Detect Suspicious mcp-dnstwist Requests to your SIEM.
• If continued use is unavoidable, implement strict input validation and sanitization on the Request argument passed to the fuzz_domain function in src/index.ts. However, this is not a substitute for patching the underlying vulnerability.