CVE-2021-4024: 
Podman vulnerability analysis and mitigation

CVE-2021-4024 is a security vulnerability discovered in podman's podman machine function, which is used to create and manage Podman virtual machines containing Podman processes. The vulnerability was disclosed in December 2021 and affects podman versions from 3.3.0 up to (excluding) 3.4.3 (NVD).

The vulnerability occurs when the podman machine function spawns a gvproxy process on the host system. The gvproxy API becomes accessible on port 7777 on all IP addresses on the host. The vulnerability has been assigned a CVSS v3.1 base score of 6.5 (Medium) with vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L (NVD).

If port 7777 is open on the host's firewall, an attacker can potentially use the gvproxy API to forward ports on the host to ports in the VM, making private services on the VM accessible to the network. Additionally, this vulnerability could be exploited to interrupt the host's services by forwarding all ports to the VM (NVD).

The vulnerability was fixed in podman version 3.4.3. Users should upgrade to this version or later to address the security issue. The fix prevents the gvproxy API from being exposed to the public internet (GitHub Release).