CVE Alert: CVE-2025-9392 – Linksys – RE6250

Risk verdict

High risk with a publicly disclosed exploit enabling remote code execution on affected Linksys routers; urgency is warranted given weaponisation potential.

Why this matters

Successful exploitation could allow an attacker to take control of the router, persist within the network, and pivot to connected hosts or other devices. The impact on confidentiality, integrity and availability is severe, with attacker capability to disrupt services or exfiltrate data from unsecured networks.

Most likely attack path

Remote attacker can trigger a stack-based overflow via the qosClassifier component without user interaction, after presenting crafted traffic. Privilege requirements are low and the attack scales across devices in scope, making lateral movement plausible within a local network or exposed segment. The same-scope nature of the vulnerability raises the risk of broader device compromise without needing administrator credentials.

Who is most exposed

Commonly deployed in homes and small offices, these Linksys models are often on networks where IoT and user devices rely on the router for QoS and routing. Exposure increases if devices are reachable from other network segments or Internet-facing management is enabled.

Detection ideas

• Unexpected reboots/crashes of the qosClassifier service or firmware component.
• Logs showing anomalous /goform/qosClassifier input parameters (dir/sFromPort/sToPort/dFromPort/dToPort/protocol/layer7/dscp/remark_dscp).
• Unusual traffic patterns or spikes coinciding with QoS classifier requests.
• Memory corruption indicators or crash dumps tied to QoS processing.

Mitigation and prioritisation

• Patch devices with the latest firmware addressing this vulnerability; apply vendor advisories promptly.
• Disable or restrict QoS classifier exposure where possible; limit management interfaces to trusted networks; enforce firewall rules to prevent remote access to vulnerable services.
• Implement network segmentation and device hardening for the affected models; schedule bulk updates and verify patch status.
• If patches are delayed, deploy compensating controls and monitor for exploitation indicators; update change-management plans accordingly.