Incus CVE-2026-115372

The attacker must be an authenticated user confined to a restricted Incus project who holds permission to create or edit custom volumes (CVSS PR:L). Exploitation to root requires targeting a storage pool that formats on copy - the advisory names non-thin LVM - because only those pools reach the root-executed mkfs call where the injected block.create_options arguments take effect (this is the AT:P attack requirement). On drivers that do not format on copy, the forbidden option still lands on the volume config but does not reach mkfs, so code execution does not occur. Mitigations per the advisory: do not grant custom-volume creation to restricted projects on pools that format on copy, or set volume.block.create_options on the pool so the pool default applies; the complete fix is upgrading to Incus 7.5.0.

This is a genuine high-priority issue for the environments that run it, though the signals are mixed on breadth versus depth. The CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:L) describes a network-reachable flaw requiring only low privileges - a user already confined to a restricted Incus project - with an attack requirement (AT:P) that reflects the real constraint that only pools formatting on copy reach the vulnerable mkfs call. Impact is maximal and confirmed by the vector: VC:H/VI:H/VA:H plus subsequent-system impact SC:H/SI:H/SA:H, consistent with argument injection into a command run as root, which breaks out of the project sandbox to host-level compromise. The vuln.today decision label is act_now, aligning with the severe technical impact and the authorization-bypass nature. Countervailing signals: there is NO CISA KEV listing, NO EPSS score provided, and NO verified public exploit code - only vendor/coordinator advisories (GHSA and VulnCheck). So severity is high but evidence of active or widespread exploitation is absent; treat this as a 'patch promptly because impact is root-level sandbox escape' case rather than a 'mass-exploited in the wild' case. Note also the input tag 'Authentication Bypass' is inaccurate - this is an authorization/project-restriction bypass (the user is already authenticated), which does not change severity but should be corrected to avoid mischaracterizing the flaw.

A user limited to a restricted Incus project who has permission to create or edit custom volumes sets block.create_options on a volume, then issues a copy or move of that volume onto a pool that formats on copy (for example non-thin LVM). The inherited option is appended to the mkfs command line that Incus runs as root, injecting attacker-controlled arguments and yielding host-level compromise. No verified working public exploit code has been identified; only coordinated vendor advisories (GHSA-4cph-ccqv-hm3c and VulnCheck) are available.