CVE-2024-27656 is a buffer overflow vulnerability identified in the D-Link DIR-823G A1V1.0.2B05 router firmware. The vulnerability arises from improper handling of the HTTP Cookie parameter, which can be manipulated by an attacker to overflow a buffer in the device’s software. This overflow can lead to a denial of service (DoS) by crashing the device or, more critically, enable remote code execution (RCE), allowing an attacker to execute arbitrary code on the router remotely. The vulnerability does not require any authentication or user interaction, increasing its risk profile. The CVSS v3.1 score of 8.8 indicates a high severity with attack vector being adjacent network (AV:A), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). The underlying weakness is classified under CWE-121, which relates to stack-based buffer overflows. Although no public exploits have been reported yet, the potential for exploitation is significant given the router’s exposure in home and small business networks. No patches or firmware updates have been announced at the time of publication, leaving affected devices vulnerable. The vulnerability’s exploitation could allow attackers to disrupt network connectivity, intercept or manipulate traffic, or gain persistent control over the device, posing serious security risks.

The impact of CVE-2024-27656 is substantial for organizations and individuals using the D-Link DIR-823G router. Successful exploitation can lead to complete compromise of the router, enabling attackers to disrupt network availability through denial of service or gain unauthorized access via remote code execution. This can result in interception or manipulation of sensitive data passing through the router, undermining confidentiality and integrity. For businesses, this could mean loss of critical network connectivity, exposure of internal communications, and potential pivoting into internal networks for further attacks. Home users risk loss of internet access and exposure of personal data. The vulnerability’s ease of exploitation without authentication or user interaction increases the likelihood of attacks, especially in environments where the router’s management interface is exposed to adjacent networks or the internet. The absence of a patch exacerbates the risk, making timely mitigation critical. Additionally, compromised routers could be leveraged as part of botnets or for launching further attacks, amplifying the threat landscape.

To mitigate CVE-2024-27656, organizations and users should immediately restrict access to the router’s management interface by disabling remote management features and limiting access to trusted networks only. Network segmentation should be employed to isolate the router from critical systems. Deploy network intrusion detection and prevention systems (IDS/IPS) capable of identifying anomalous HTTP requests, particularly those with suspicious Cookie parameters. Monitor network traffic for unusual patterns indicative of exploitation attempts. Regularly check for firmware updates from D-Link and apply them promptly once available. If possible, consider replacing affected devices with models that have received security updates or have a better security track record. Employ strong network perimeter defenses such as firewalls to block unauthorized access to the router. Additionally, educate users about the risks of exposing router management interfaces and encourage secure configuration practices. For organizations, conducting vulnerability assessments and penetration testing targeting network infrastructure can help identify exposure to this and similar vulnerabilities.