CVE-2025-13400 is a buffer overflow vulnerability identified in the Tenda CH22 router firmware version 1.0.0.1. The flaw resides in the formWrlExtraGet function, specifically within the /goform/WrlExtraGet endpoint, where the chkHz parameter is improperly handled. An attacker can remotely send a specially crafted request manipulating the chkHz argument to overflow a buffer, leading to memory corruption. This memory corruption can be leveraged to execute arbitrary code on the device with elevated privileges, potentially allowing full control over the router. The vulnerability requires no authentication or user interaction, making it highly exploitable over the network. The CVSS 4.0 base score is 8.7, reflecting its high impact on confidentiality, integrity, and availability. The exploit has been publicly disclosed, increasing the likelihood of active exploitation. No official patches have been linked yet, and no confirmed in-the-wild exploitation has been reported. The vulnerability could be used to disrupt network operations, intercept or manipulate traffic, or pivot into internal networks. Given the critical role of routers in network infrastructure, this vulnerability poses a serious security risk to organizations and individuals using affected devices.

The impact of CVE-2025-13400 is significant for organizations relying on Tenda CH22 routers. Successful exploitation can lead to complete compromise of the device, allowing attackers to execute arbitrary code remotely without authentication. This can result in interception or manipulation of network traffic, disruption of network availability, and potential lateral movement into internal networks. Confidential data passing through the router could be exposed or altered, undermining data integrity and privacy. The vulnerability could also be exploited to create persistent backdoors or launch further attacks against connected systems. Organizations with large deployments of Tenda CH22 devices are at heightened risk, especially if devices are exposed to untrusted networks or the internet. The public availability of exploit code increases the urgency to address this vulnerability to prevent widespread attacks.

1. Immediate mitigation should focus on isolating affected Tenda CH22 devices from untrusted networks, especially the internet, to reduce exposure. 2. Monitor network traffic for unusual activity targeting the /goform/WrlExtraGet endpoint or suspicious chkHz parameter values. 3. Implement network-level filtering or firewall rules to block or restrict access to the vulnerable endpoint from external sources. 4. Regularly check for firmware updates or security advisories from Tenda and apply patches as soon as they become available. 5. If patches are not yet released, consider replacing affected devices with alternative hardware that is not vulnerable. 6. Employ network segmentation to limit the impact of a compromised router on critical internal systems. 7. Conduct vulnerability scans and penetration tests to identify any exploitation attempts. 8. Educate IT staff about this vulnerability and ensure incident response plans include steps for router compromise scenarios.