Incus contains an arbitrary file write flaw in the sftpRecursivePullFile routine that permits a malicious incus-agent to escape the designated target directory during a recursive pull. An attacker with root privileges inside a virtual machine can exploit duplicate path entries reported as symlinks, then files or directories, to write arbitrary data such as /etc/shadow onto the operator's host system. The weakness is a classic filesystem traversal error (CWE-59) that can lead to unauthorized modification of critical host files, enabling further compromise.

The vulnerability is present in Incus versions prior to 6.0.7, 6.1.0 before 7.0.2, and 7.1.0 before 7.5.0. Affected deployments use the lxc:incus product line.

With a CVSS score of 6.9 the flaw is considered moderate. No EPSS data is available and the existence of the vulnerability is not yet listed in the CISA KEV catalog, suggesting no publicly documented exploits. However, the required conditions—root access within a virtual machine and the ability to issue a recursive file pull—may be met in small to medium environments where VMs are trusted. If an attacker can meet these prerequisites, they can gain arbitrary host file write permissions, silently undermining system integrity and potentially achieving full control of the host.