Altair is a fork of Misskey v12. Affected versions lack of request validation and lack of authentication in the image proxy for compressing and resizing remote files could allow attacks that could affect availability, such as by abnormally increasing the CPU usage of the server on which this software is running or placing a heavy load on the network it is using. This issue has been fixed in v12.24Q4.1. Users are advised to upgrade. There are no known workarounds for this vulnerability.
The product does not properly control the allocation and maintenance of a limited resource.
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.