The vulnerability is caused by multiple stack overflows within the fromVirtualSer function of the Tenda O3 Wireless Router. Attackers can trigger these overflows by sending specially crafted HTTP requests that manipulate the puVar2, puVar1, __s2, __s1_00, and puVar3 parameters. When the overflow occurs, it corrupts the router’s stack, causing the device to crash or become unresponsive. The impact is limited to availability; there is no direct compromise of confidentiality or integrity.

Shenzhen Tenda Technology Co., Ltd. Tenda O3 Wireless Router, firmware version 1.0.0.5 (build 4180). No other vendors or product revisions are currently identified as affected.

The CVSS score of 7.5 indicates a high severity level, while the EPSS score of less than 1% suggests a low probability that the vulnerability is actively exploited at present. The router must be reachable over the local network or the internet for an attacker to send the malicious HTTP request, so the likelihood of exploitation depends on the router’s exposure. The router’s availability can be disrupted, potentially affecting all users reliant on the device, yet the vulnerability is not listed in the CISA KEV catalog.