CVE-2026-103397: OpenSave before 2.4.0-beta.1 Authentication Bypass via Spoofed Relay Sender
OpenSave before 2.4.0-beta.1 fails to validate sender identity in WAN relay requests, allowing unpaired room members to impersonate paired devices by spoofing the RelayMessage From field. Attackers who know the room code can join, read paired peer identifiers from announcements, and send forged requests to access protected sync routes including save data, snapshots, and file operations.
Affected Software
Event History
Frequently Asked Questions
Who is exposed to this issue?
OpenSave deployments using versions before 2.4.0-beta.1 are exposed when they use WAN relay requests and have rooms that an attacker can join with a known room code. Unpaired room members can target paired devices in those rooms.
What does an attacker need to exploit it?
The attacker needs the room code to join the room. After joining, they can obtain paired peer identifiers from announcements and spoof the RelayMessage From field in requests sent through the WAN relay.
What access can exploitation provide?
A successful attacker can impersonate a paired device to reach protected sync routes. The described targets include save data, snapshots, and file operations.
How can I determine whether my deployment is affected?
Check whether the OpenSave version is earlier than 2.4.0-beta.1 and whether WAN relay functionality is in use. Also assess whether room codes could be known by or disclosed to untrusted users, since knowledge of a room code enables joining the room.