Yan Jia

In the `lxc-copy` utility and the public `lxc container::clone()` API, a flaw exists where the process can follow attacker-controlled symbolic links when updating the `/etc/hostname` file in a copied container root filesystem. This occurs when a privileged cloning process running as root clones a source rootfs that is attacker-controlled or less trusted. If a symlink is placed at `etc/hostname` or within an intermediate component, the clone operation preserves this symlink. When the process attempts to update the hostname without the `LXC CLONE KEEPNAME` flag, the write operation can resolve outside the destination rootfs, allowing the privileged process to truncate and overwrite an existing host file with the destination container name.

The issue is related to the implementation of the MQTT v5 protocol in Eclipse Mosquitto, which can cause excessive CPU usage. This can be exploited by a remote attacker to cause a denial of service. The problem occurs when an MQTT v5 client connects with a large number of `user-property` properties.

This issue was addressed with improved setting propagation. An attacker in a privileged network position may be able to unexpectedly alter application state.

The issue is related to insufficient access control in the Eclipse Mosquitto message broker. It may allow a remote attacker to gain unauthorized access to protected information. In certain applications, this could result in clients being able to cause effects that would otherwise not be allowed, such as publishing retained messages to topics they no longer have access to.

Name of the Vulnerable Software and Affected Versions: Eclipse Mosquitto versions 1.0 through 1.5.5 Description: The issue is related to the configuration of the access control list (ACL) file in Eclipse Mosquitto. When the ACL file is empty or contains only comments or blank lines, Mosquitto previously used a default allow policy. However, the new behavior is to deny all access if the ACL file is empty. This change in behavior may lead to unexpected configuration issues. The vulnerability is also related to insufficient input validation and incorrect implementation of functions, which may allow a remote attacker to gain unauthorized access to protected information. Recommendations: For Eclipse Mosquitto versions 1.0 through 1.5.5, ensure that the ACL file is properly configured and not empty to avoid denying all access. As a temporary workaround, consider defining a default ACL policy to minimize the risk of exploitation. Restrict access to the broker until a proper ACL configuration is in place.