CVE-2022-42081 is a high-severity vulnerability identified in the firmware version V15.03.06.23_multi_TD01 of the Tenda AC1206 US_AC1206V1.0RTL router. The vulnerability is a stack overflow triggered via the sched_end_time parameter. A stack overflow occurs when a program writes more data to a buffer located on the stack than it can hold, potentially overwriting adjacent memory and leading to unpredictable behavior, including crashes or arbitrary code execution. In this case, the sched_end_time parameter, likely part of the router's scheduling or configuration interface, does not properly validate input size or bounds, allowing an attacker to overflow the stack. The CVSS 3.1 base score of 7.5 reflects a high severity, with the vector indicating that the vulnerability can be exploited remotely over the network (AV:N), requires no privileges (PR:N), and no user interaction (UI:N). The impact is limited to availability (A:H), meaning successful exploitation would cause denial of service, such as device crashes or reboots, but does not compromise confidentiality or integrity. No known exploits are reported in the wild, and no patches have been linked, suggesting that mitigation may rely on vendor updates or workarounds. The vulnerability is categorized under CWE-787 (Out-of-bounds Write), a common and dangerous class of memory corruption bugs. Given the affected product is a consumer-grade router model, exploitation could disrupt network availability for users relying on this device. The lack of vendor and product metadata limits detailed attribution but the specific firmware version and model are identified.

For European organizations, especially small and medium enterprises or home offices using the Tenda AC1206 router, this vulnerability poses a risk of network disruption through denial of service. While it does not directly lead to data breaches or unauthorized access, loss of availability can impact business operations, remote work, and connectivity. Critical infrastructure or organizations relying on these routers for network access may experience outages, affecting productivity and potentially leading to financial losses. Additionally, if exploited at scale, widespread router downtime could degrade internet service quality in affected regions. The absence of known exploits reduces immediate risk, but the ease of remote exploitation without authentication means attackers could weaponize this vulnerability in targeted denial-of-service campaigns. European organizations with limited IT support or outdated firmware management practices are particularly vulnerable to prolonged exposure.

Given the lack of an official patch or vendor advisory, European organizations should take proactive steps to mitigate risk. First, identify and inventory all Tenda AC1206 routers in use, verifying firmware versions to detect vulnerable devices. If possible, upgrade to the latest firmware version provided by Tenda that addresses this vulnerability; if no update is available, consider temporary mitigations such as disabling remote management interfaces or restricting access to the router's configuration ports via firewall rules. Network segmentation can limit exposure by isolating vulnerable devices from critical infrastructure. Monitoring network traffic for unusual patterns or repeated malformed sched_end_time parameter attempts can help detect exploitation attempts. Organizations should also engage with Tenda support channels to request patches or guidance. For high-risk environments, replacing vulnerable routers with models from vendors with active security support may be warranted. Finally, maintain regular backups of router configurations to enable rapid recovery after potential crashes.