CVE-2026-48749 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 can be used to read or create/write arbitrary files on the host; possibly leading to arbitrary command execution. Version 7.2.0 fixes the issue.
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Analysis
by VulDB Data Team • 08/21/2026
Incus serves as a robust system container and virtual machine manager designed for Linux environments, facilitating efficient orchestration of isolated computing resources. However, prior to version 7.2.0, the software contained a critical security flaw related to image handling that allowed attackers with access to specific API endpoints or administrative privileges to exploit improper validation mechanisms within the image processing pipeline. This vulnerability stems from insufficient sanitization and path traversal checks when Incus processes container images, particularly those involving root filesystem extraction and configuration parsing. A specially crafted image can manipulate internal file paths during the import or creation process, effectively bypassing standard sandbox boundaries that are meant to restrict operations to designated directories within the host system.
The technical nature of this flaw involves a path traversal vulnerability where user-supplied data in an image archive is not adequately validated against directory traversal sequences such as dot-dot-slash patterns before being applied to the host filesystem. When Incus extracts or writes files from these images, it fails to enforce strict canonicalization checks on file paths relative to the intended container rootfs location. This oversight allows a malicious actor to write arbitrary content to sensitive system locations outside of the container environment, such as configuration directories in /etc, binary execution paths in /usr/bin, or user home directories containing shell initialization scripts like .bashrc or .profile. By overwriting these files with carefully crafted payloads, an attacker can achieve remote code execution on the host operating system without requiring additional privilege escalation exploits beyond those already granted by their Incus access level.
The operational impact of this vulnerability is severe, as it effectively breaks the isolation guarantees provided by containerization technologies like LXC and Incus itself. Successful exploitation leads to arbitrary command execution with the privileges of the Incus daemon process, which typically runs under a dedicated system user but may have elevated capabilities depending on configuration settings such as rootless mode or specific device permissions granted to containers. This compromise allows attackers to pivot from a single compromised container to full control over the underlying host infrastructure, potentially leading to data exfiltration, lateral movement across networked systems, and complete loss of integrity for all workloads hosted on that machine. The ability to read arbitrary files also enables reconnaissance activities where sensitive credentials, private keys, or proprietary source code stored on the host can be stolen by an attacker operating within a seemingly isolated container environment.
To mitigate this risk, organizations running Incus must immediately upgrade to version 7.2.0 or later, which includes patches that enforce strict path validation and canonicalization during image processing operations. Until upgrading is feasible, administrators should restrict API access using strong authentication mechanisms such as TLS client certificates and limit the privileges granted to containers by disabling unprivileged device mounts and restricting file system write permissions through Incus security profiles. Additionally, implementing network segmentation to isolate management interfaces from general workloads can reduce the attack surface available to potential exploiters. This vulnerability aligns with CWE-22 Improper Limitation of a Pathname to a Restricted Directory, highlighting the critical importance of rigorous input validation in systems that handle external archives and file system operations. From an ATT&CK perspective, this flaw facilitates Initial Access via compromised credentials or API keys followed by Execution through crafted image payloads, underscoring the need for continuous monitoring of container runtime activities and regular updates to container management platforms to prevent such privilege escalation scenarios.