CVE-2023-20250 is a stack-based buffer overflow vulnerability found in the web-based management interface of Cisco Small Business RV Series routers, specifically models RV110W, RV130, RV130W, and RV215W. The vulnerability arises from improper validation of requests sent to the router's web interface, allowing an attacker who has authenticated with valid administrator credentials to send specially crafted requests that overflow a stack buffer. This overflow enables the attacker to execute arbitrary code with root privileges on the affected device. The flaw affects a broad range of firmware versions, from early releases like 1.0.0.2 up to 1.3.1.7. Exploitation requires network access to the management interface and valid admin credentials, but no additional user interaction is needed. The vulnerability could allow attackers to take full control of the router, potentially leading to interception or manipulation of network traffic, disruption of network services, or use of the device as a foothold for further attacks within an organization's network. Cisco has published the vulnerability with a CVSS v3.1 score of 6.5, indicating medium severity, reflecting the requirement for high privileges (admin credentials) but the significant impact of root-level code execution. No public exploits or active exploitation in the wild have been reported to date. The vulnerability underscores the importance of securing administrative access and timely patching of network infrastructure devices.

For European organizations, this vulnerability poses a significant risk to network security and operational integrity. Successful exploitation could lead to full compromise of affected routers, enabling attackers to intercept, modify, or redirect sensitive data traversing these devices. This could impact confidentiality and integrity of communications, especially for small and medium enterprises relying on these routers for secure connectivity. Additionally, attackers could disrupt network availability indirectly by manipulating routing or firewall functions. Given the root-level access gained, attackers might also pivot to internal networks, escalating the threat to broader organizational assets. The requirement for valid administrator credentials limits the attack surface but does not eliminate risk, especially if credential management is weak or if attackers gain credentials through phishing or insider threats. European organizations with remote management enabled or exposed management interfaces are particularly vulnerable. The absence of known exploits in the wild provides a window for mitigation, but the widespread use of Cisco Small Business RV Series routers in Europe means the potential impact is considerable if left unaddressed.

Organizations should immediately verify if they use any affected Cisco Small Business RV Series router models and identify the firmware versions in use. Cisco should be consulted for available patches or firmware updates addressing this vulnerability; if patches are not yet available, organizations should apply any recommended workarounds or mitigations from Cisco advisories. Restricting access to the web-based management interface is critical—this includes limiting administrative access to trusted internal networks or VPNs, disabling remote management if not necessary, and enforcing strong, unique administrator passwords. Implement network segmentation to isolate management interfaces from general user networks. Regularly audit and monitor router logs for suspicious administrative activity. Employ multi-factor authentication (MFA) for administrative access where supported. Additionally, organizations should conduct credential hygiene reviews to ensure administrator credentials have not been compromised. Finally, prepare incident response plans to quickly address potential exploitation attempts.