CVE-2026-3377 is a buffer overflow vulnerability identified in the Tenda F453 router firmware version 1.0.0.3. The vulnerability resides in the fromSafeUrlFilter function located in the /goform/SafeUrlFilter endpoint. Specifically, the issue arises from improper validation and handling of the 'page' parameter, which can be manipulated by a remote attacker to overflow a buffer. This overflow can corrupt memory, potentially allowing the attacker to execute arbitrary code on the device. The vulnerability is remotely exploitable without requiring authentication or user interaction, making it particularly dangerous. The CVSS 4.0 base score is 8.7, indicating a high severity level, with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (VC:H/VI:H/VA:H). Although no active exploitation has been reported yet, a public exploit is available, increasing the likelihood of future attacks. The affected product, Tenda F453, is a consumer and small business router commonly deployed in various regions. The vulnerability could allow attackers to gain control over the device, disrupt network operations, or pivot to other internal systems.

The impact of CVE-2026-3377 is significant for organizations using Tenda F453 routers, as exploitation can lead to full compromise of the device. This includes unauthorized access to network traffic, interception or modification of data, disruption of network services, and potential lateral movement within the network. Given the router's role as a gateway device, attackers could establish persistent footholds, launch further attacks against internal systems, or exfiltrate sensitive information. The lack of authentication and user interaction requirements lowers the barrier for exploitation, increasing the risk of widespread attacks. Organizations relying on these routers for critical connectivity or security functions may face operational downtime, data breaches, and reputational damage. Additionally, compromised routers could be leveraged in botnets or other malicious infrastructures, amplifying the threat landscape.

To mitigate CVE-2026-3377, organizations should first check for firmware updates or patches from Tenda addressing this vulnerability and apply them promptly. If no official patch is available, network administrators should restrict access to the /goform/SafeUrlFilter endpoint by implementing firewall rules or access control lists (ACLs) to limit exposure to trusted management networks only. Network segmentation should be employed to isolate vulnerable devices from critical infrastructure and sensitive data. Monitoring network traffic for unusual requests targeting the vulnerable endpoint can help detect exploitation attempts early. Disabling remote management features or changing default credentials can reduce attack surface. Additionally, organizations should consider replacing affected devices with models that have a stronger security posture if patching is not feasible. Regular vulnerability scanning and penetration testing can help identify residual risks related to this vulnerability.