CVE-2025-5622 in DIR-816
Summary
by MITRE • 06/05/2025
A vulnerability was found in D-Link DIR-816 1.10CNB05 and classified as critical. Affected by this issue is the function wirelessApcli_5g of the file /goform/wirelessApcli_5g. The manipulation of the argument apcli_mode_5g/apcli_enc_5g/apcli_default_key_5g leads to stack-based buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. This vulnerability only affects products that are no longer supported by the maintainer.
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Analysis
by VulDB Data Team • 06/06/2025
The vulnerability identified as CVE-2025-5622 represents a critical stack-based buffer overflow in D-Link DIR-816 router firmware version 1.10CNB05. This flaw exists within the wirelessApcli_5g function located in the /goform/wirelessApcli_5g file, which handles wireless client mode configuration for the 5GHz band. The vulnerability stems from inadequate input validation when processing the apcli_mode_5g, apcli_enc_5g, and apcli_default_key_5g parameters, creating an exploitable condition that allows attackers to overwrite adjacent stack memory locations. The attack vector is remote, meaning malicious actors can trigger this vulnerability without physical access to the device, making it particularly dangerous for networked environments. According to industry standards, this vulnerability maps to CWE-121 Stack-based Buffer Overflow, which is classified as a critical weakness in software security architecture. The ATT&CK framework categorizes this as a privilege escalation technique through software exploitation, where attackers can leverage the buffer overflow to execute arbitrary code with elevated privileges. The fact that this vulnerability has been publicly disclosed and is actively being used in the wild significantly increases the risk to affected systems, as it eliminates the element of surprise that typically protects against zero-day exploits.
The technical implementation of this buffer overflow occurs when the router processes user-supplied input parameters through the wirelessApcli_5g form handler. When an attacker sends specially crafted parameters containing excessive data in the apcli_mode_5g, apcli_enc_5g, or apcli_default_key_5g fields, the router's memory management fails to properly bounds-check the input before copying it to fixed-size stack buffers. This results in memory corruption that can be leveraged to overwrite return addresses, function pointers, or other critical stack data structures. The stack-based nature of this vulnerability means that the attacker can potentially control the instruction pointer and redirect execution flow to malicious code. The impact extends beyond simple code execution to include complete system compromise, as the router's administrative interface and network services become vulnerable to manipulation. The vulnerability's remote exploitability means that attackers can target these devices from anywhere on the internet, provided they can reach the router's web interface or management ports. The fact that the affected firmware version 1.10CNB05 is no longer supported by the manufacturer creates a particularly concerning scenario where no official patches or updates are available to remediate the issue, leaving users exposed to ongoing exploitation attempts.
The operational impact of CVE-2025-5622 extends far beyond simple network disruption, as compromised routers can become part of botnets, serve as pivoting points for internal network attacks, or provide persistent backdoors for unauthorized access. An attacker who successfully exploits this vulnerability can gain root access to the router's operating system, potentially enabling them to modify network configurations, redirect traffic through malicious proxies, or establish persistent access to the internal network. The vulnerability's critical classification indicates that it can be exploited without user interaction, making it particularly dangerous for residential and small office environments where network security is often less sophisticated. The lack of support for the affected firmware version compounds the security risk, as organizations cannot rely on vendor-provided security updates to protect against this specific threat. Network administrators should consider this vulnerability as a high-priority threat that requires immediate remediation through device replacement or hardware upgrade, as the risk of exploitation remains constant and the attack surface continues to expand with public disclosure. The vulnerability's presence in a consumer-grade router also highlights the broader security challenges faced by IoT and networking equipment vendors who may not provide long-term security support for older products, creating persistent risks for users who continue to operate unsupported devices.
The recommended mitigation strategies for CVE-2025-5622 focus on immediate hardware replacement due to the lack of available patches for the unsupported firmware version. Organizations and individuals should upgrade to newer router models that are actively supported by D-Link or other manufacturers with established security update policies. Network segmentation and firewall rules should be implemented to limit exposure of affected devices to external networks, while monitoring systems should be deployed to detect potential exploitation attempts. The use of network intrusion detection systems can help identify anomalous traffic patterns that may indicate exploitation activity, particularly around the router's web interface ports. Additionally, administrators should consider implementing network access control measures that restrict administrative access to these devices to trusted IP addresses only, reducing the attack surface for remote exploitation attempts. Regular network audits should be conducted to identify all instances of affected D-Link devices and ensure complete remediation of the vulnerability across all network infrastructure. The vulnerability also underscores the importance of maintaining up-to-date firmware and implementing robust security practices for network equipment, as the lack of vendor support for legacy firmware versions leaves systems vulnerable to ongoing exploitation attempts.