Vulnerabilities in Kaon AR2140 routers

CERT Polska has received a report about vulnerabilities in firmware of Kaon AR2140 routers and participated in coordination of their disclosure.

The vulnerabilityCVE-2026-52748: The Kaon AR2140 router contains a vulnerability where the backup functionality is accessible without authentication. This allows an unauthenticated remote attacker to trigger a configuration backup and retrieve it in a form encrypted by a device-specific key. Triggering this function renders the router inoperable for a substantial period of time.

The vulnerabilityCVE-2026-52749: The Kaon AR2140 router improperly issues session cookies in responses to unauthenticated HTTP requests. This vulnerability allows a remote attacker to obtain a valid session identifier without providing credentials, resulting in an authentication bypass. With this access, the attacker can perform unauthorized actions on upgrade-related functionalities. These actions can be abused to force the router to issue GET requests to arbitrarily chosen domains.

These issues were identified in firmware versions up to 4.2.17. Status of newer versions remains unknown.

We thank Sebastian Jeż for the responsible vulnerability report.