Incus, a system container and virtual machine manager, contains a flaw in its use of pongo2 templates that allows an attacker to read or modify any file on the host system with root privileges. The vulnerability arises because the chroot isolation intended to confine template execution is bypassed, enabling the template to access the entire host filesystem. This weakness corresponds to CWE‑1336 (Improper Validation of Runtime Parameters) and CWE‑243 (Resource Disconnection Without Cleanup). The result is a serious threat to confidentiality, integrity, and availability, since an attacker could exfiltrate sensitive data, alter critical system files, or even deploy malicious code.

All Incus installations running versions earlier than 6.23.0 are impacted. The vulnerability affects the core Incus product from Linux Containers, regardless of deployment mode. No additional vendor or product variations are reported.

The CVSS score of 10 indicates maximal severity, and the EPSS score of below 1% suggests the likelihood of real‑world exploitation is low at present. However, because the attack requires only the ability to supply a pongo2 template to an instance, the potential attack vector is relatively simple once an instance is reachable. The vulnerability is not listed in the CISA KEV catalog, but its high impact warrants immediate attention. Once exploited, an attacker gains full read/write access to the host filesystem, effectively compromising the entire platform.