CVE-2025-9246 in RE6250
Summary
by MITRE • 08/20/2025
A flaw has been found in Linksys RE6250, RE6300, RE6350, RE6500, RE7000 and RE9000 1.0.013.001/1.0.04.001/1.0.04.002/1.1.05.003/1.2.07.001. Impacted is the function check_port_conflict of the file /goform/check_port_conflict. Executing manipulation of the argument single_port_rule/port_range_rule can lead to stack-based buffer overflow. The attack can be executed remotely. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 09/03/2025
This vulnerability exists in multiple Linksys router models including RE6250, RE6300, RE6350, RE6500, RE7000, and RE9000 running specific firmware versions. The flaw is located within the check_port_conflict function in the /goform/check_port_conflict file which handles port configuration validation. The vulnerability manifests as a stack-based buffer overflow when processing user-supplied input through the single_port_rule or port_range_rule arguments. This type of vulnerability falls under CWE-121 which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent stack memory locations. The attack vector is remote, meaning an unauthenticated attacker can exploit this vulnerability without requiring physical access to the device or prior authentication.
The technical implementation of this vulnerability demonstrates a classic buffer overflow scenario where the device fails to properly validate the length of input data before copying it into fixed-size stack buffers. When an attacker crafts malicious input for the single_port_rule or port_range_rule parameters, the system does not perform adequate bounds checking, allowing the overflow to occur. This condition can be exploited to execute arbitrary code on the affected devices, potentially leading to complete system compromise. The vulnerability is particularly concerning because it affects multiple router models and firmware versions, indicating a widespread issue within the Linksys product line. The fact that an exploit has been published and is believed to be actively used increases the risk profile significantly.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete network compromise and potential data exfiltration. Compromised routers can serve as entry points for broader network attacks, allowing attackers to establish persistent access, redirect traffic, or launch further attacks against internal network resources. The vulnerability's remote nature means that attackers can target these devices from anywhere on the internet without requiring network proximity. This type of attack aligns with ATT&CK technique T1071.004 which covers application layer protocol: dns tunneling, as compromised routers can be used to establish covert communication channels. Additionally, the vulnerability could enable attackers to manipulate network traffic, potentially leading to man-in-the-middle attacks or denial of service conditions that disrupt network availability.
Mitigation strategies should include immediate firmware updates from Linksys if available, though the vendor's lack of response to early disclosure suggests delayed patch availability. Network segmentation and firewall rules should be implemented to restrict access to affected devices, particularly limiting remote administrative access to only trusted networks. Monitoring for unusual network traffic patterns or unauthorized configuration changes can help detect exploitation attempts. The affected devices should be isolated from critical network segments until proper patches are applied. Organizations should consider implementing intrusion detection systems that can identify malicious traffic patterns associated with buffer overflow exploits. Regular vulnerability assessments and penetration testing should be conducted to identify similar issues in other network infrastructure components, as this vulnerability demonstrates a pattern of insufficient input validation in embedded network devices. The lack of vendor response highlights the importance of proactive security measures and the need for organizations to maintain internal patching capabilities for critical infrastructure components.