CVE-2025-57623 in N600R firmware
Summary
by MITRE • 09/25/2025
A NULL pointer dereference in TOTOLINK N600R firmware v4.3.0cu.7866_B2022506 allows attackers to cause a Denial of Service.
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Analysis
by VulDB Data Team • 09/27/2025
The vulnerability identified as CVE-2025-57623 represents a critical NULL pointer dereference flaw within the TOTOLINK N600R wireless router firmware version 4.3.0cu.7866_B2022506. This issue manifests as a denial of service condition that can be exploited by remote attackers to disrupt the normal operation of the affected device. The vulnerability stems from improper input validation within the firmware's processing logic, specifically in how the system handles certain network requests or configuration parameters that may lead to a NULL pointer reference during execution. Such flaws typically occur when software attempts to access memory through a pointer that has not been properly initialized or has been set to NULL, resulting in a system crash or reboot.
The technical implementation of this vulnerability involves the firmware's failure to validate incoming data or parameters before attempting to dereference pointers within its processing functions. When an attacker crafts malicious input that triggers this condition, the router's execution flow encounters a NULL pointer access, causing the system to terminate unexpectedly. This behavior aligns with CWE-476, which specifically addresses NULL pointer dereference vulnerabilities in software systems. The impact of this vulnerability extends beyond simple service disruption as it can be leveraged to create persistent denial of service conditions that may require manual intervention to restore normal operation, including firmware reinstallation or physical device reset procedures.
From an operational perspective, this vulnerability presents significant risks to network availability and stability within environments where TOTOLINK N600R devices are deployed. The remote exploitation capability means that attackers can potentially disrupt network services without requiring physical access or local network presence, making this a particularly concerning issue for both enterprise and residential network infrastructures. The device's role as a primary network gateway makes it a prime target for attackers seeking to establish persistent network disruption or as part of larger attack campaigns targeting network availability. This vulnerability can be classified under the ATT&CK technique T1499.004, which covers network disruption through service availability attacks, and represents a direct threat to the availability component of the CIA triad.
Effective mitigation strategies for CVE-2025-57623 must include immediate firmware updates from TOTOLINK to address the underlying NULL pointer dereference issue. Network administrators should implement monitoring solutions to detect unusual traffic patterns or device reboots that may indicate exploitation attempts. Additional defensive measures include network segmentation to limit the impact of potential exploitation, implementing intrusion detection systems that can identify malformed packets targeting this specific vulnerability, and establishing robust patch management procedures to ensure timely firmware updates across all affected devices. Organizations should also consider disabling unnecessary services and ports on affected routers to minimize the attack surface while awaiting official patches. The vulnerability demonstrates the importance of proper input validation and memory management practices in embedded systems, highlighting the need for comprehensive security testing during firmware development cycles to prevent similar issues from emerging in production environments.