Overview
The cybersecurity world is continuously evolving, and with it comes an alarming rise in vulnerabilities. One such vulnerability that has come to light recently is CVE-2025-30256. This vulnerability resides in the HTTP Header Parsing functionality of the Tenda AC6 V5.0 V02.03.01.110, a widely used router. The flaw can be exploited to cause a Denial of Service (DoS) condition, potentially leading to system compromise or data leakage. The severity of this vulnerability and its widespread impact necessitate immediate attention and proactive mitigation.
Vulnerability Summary
CVE ID: CVE-2025-30256
Severity: High (CVSS: 8.6)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Denial of Service, Potential System Compromise, and Data Leakage
Affected Products
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Product | Affected Versions
Tenda AC6 | V5.0 V02.03.01.110
How the Exploit Works
The exploit works by having an attacker send a specially crafted series of HTTP requests to the vulnerable system. These malformed requests trigger a fault in the HTTP Header Parsing functionality of the Tenda AC6 router. The system is unable to handle these malformed requests, leading to a reboot of the system. This reboot can disrupt services and opens an opportunity for further exploitation, potentially leading to system compromise or data leakage.
Conceptual Example Code
Here is a conceptual example of such a malformed HTTP request that could exploit this vulnerability:
GET / HTTP/1.1
Host: target.example.com
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64)
Connection: keep-alive
Content-Length: 99999999999In this example, the “Content-Length” header is set to an excessively high value. The system attempts to allocate memory for the incoming data based on the “Content-Length” value. However, the excessive value leads to memory exhaustion, causing the system to reboot.
Mitigation Guidance
To mitigate this vulnerability, users are advised to apply the vendor-provided patch as soon as possible. If a patch is not yet available or cannot be applied immediately, users can use a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to block or alert on suspicious network traffic patterns associated with this vulnerability. These systems can serve as a temporary mitigation measure until the patch can be applied.
Remember, staying updated with patches and employing robust security measures is the first line of defense against such vulnerabilities.
