TOTOLINK X5000R V9.1.0cu.2415_B20250515 contains a denial-of-service vulnerability in /cgi-bin/cstecgi.cgi. The CGI reads the CONTENT_LENGTH environment variable and allocates memory using malloc (CONTENT_LENGTH + 1) without sufficient bounds checking. When lighttpd s request size limit is not enforced, a crafted large POST request can cause memory exhaustion or a segmentation fault, leading to a crash of the management CGI and loss of availability of the web interface.
Weakness
The product does not properly control the allocation and maintenance of a limited resource.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| X5000r_firmware | Totolink | 9.1.0cu.2415_b20250515 (including) | 9.1.0cu.2415_b20250515 (including) |
Potential Mitigations
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/147.html
- https://cwe.mitre.org/data/definitions/227.html
- https://cwe.mitre.org/data/definitions/492.html