CVE-2026-48752 in Incus
Summary
by MITRE • 08/21/2026
Incus is a system container and virtual machine manager. Prior to version 7.2.0, a specially crafted image or instance backup can be used to read or create/write arbitrary files on the host; possibly leading to arbitrary command execution. Version 7.2.0 patches the issue.
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Analysis
by VulDB Data Team • 08/21/2026
Incus is an open-source system container and virtual machine manager that provides infrastructure-level isolation for running multiple isolated systems, known as containers or VMs, on a single host using Linux kernel features such as namespaces and cgroups. The software serves as a successor to LXD, offering enhanced security profiles, improved networking capabilities, and support for both unprivileged containers and full virtual machines. As with any system management tool that interacts deeply with the operating system kernel and file systems, Incus requires strict adherence to privilege separation principles to prevent container escape or host compromise. The vulnerability identified in versions prior to 7.2.0 represents a critical failure in input validation during the processing of image archives and instance backup files, which are commonly used for migration, restoration, and snapshot management operations within the platform.
The core technical flaw lies in how Incus handles tar-based archive extraction when importing images or restoring backups from untrusted sources. Specifically, the vulnerability allows an attacker who can supply a specially crafted image file or instance backup to perform path traversal attacks during the extraction process. By manipulating directory structures and symbolic links within the archived files, it is possible to escape the intended target directory on the host filesystem. This lack of proper sanitization enables the reading of arbitrary files from locations outside the container's sandboxed environment, such as /etc/shadow or SSH keys, leading to information disclosure. More critically, if the extraction process allows for file creation in writable directories with specific permissions, an attacker can write malicious scripts or binaries into paths that are subsequently executed by privileged processes running on the host system.
The operational impact of this vulnerability is severe due to its potential to lead to arbitrary command execution on the host machine. Since Incus typically runs as a root process or interacts closely with root-level operations to manage namespaces and cgroups, successful exploitation grants an attacker full control over the underlying host operating system. This effectively nullifies the security boundaries provided by containerization, allowing lateral movement across other containers hosted on the same node and potentially compromising the entire infrastructure cluster if management APIs are exposed. The ability to read sensitive configuration files further exacerbates the risk by facilitating credential theft or network reconnaissance, which can be leveraged for more persistent attacks such as installing rootkits or establishing backdoors that survive container restarts.
This vulnerability aligns with CWE-22: Improper Limitation of a Pathname to a Restricted Directory, commonly known as path traversal, and CWE-94: Improper Control of Generation of Code (Code Injection) if the crafted files result in executable code being placed in an execution context. From a threat modeling perspective using the MITRE ATT&CK framework, this flaw facilitates Initial Access through compromised or malicious images, followed by Privilege Escalation to gain host-level control, and potentially Persistence via planted scripts or modified system configurations. The attack vector is primarily remote if Incus API endpoints are exposed without sufficient authentication controls, but it can also be exploited locally by any user with permission to import images or restore backups within the Incus environment.
To mitigate this risk, organizations running Incus must immediately upgrade to version 7.2.0 or later, where the issue has been patched through stricter validation of archive contents and improved handling of symbolic links during extraction. In addition to upgrading, administrators should enforce strict access controls on who can import images or manage backups, ensuring that only trusted users with verified identities are granted these privileges. It is also recommended to run Incus in unprivileged mode where possible, leveraging user namespaces to further isolate container processes from the host kernel and reduce the blast radius of any potential escape attempts. Regular auditing of image sources and implementing digital signature verification for imported images can provide an additional layer of defense against maliciously crafted archives designed to exploit this class of vulnerabilities.