lxc incus-os up to 20260314 PCR7 insufficiently protected credentials

Summaryinfo

A vulnerability labeled as critical has been found in lxc incus-os up to 20260314. This affects an unknown function. The manipulation of the argument PCR7 results in insufficiently protected credentials. This vulnerability is known as CVE-2026-32606. An attack on the physical device is feasible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, was found in lxc incus-os up to 20260314. Affected is an unknown part. The manipulation of the argument PCR7 with an unknown input leads to a insufficiently protected credentials vulnerability. CWE is classifying the issue as CWE-522. The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

IncusOS is an immutable OS image dedicated to running Incus. Prior to 202603142010, the default configuration of systemd-cryptenroll as used by IncusOS through mkosi allows for an attacker with physical access to the machine to access the encrypted data without requiring any interaction by the system's owner or any tampering of Secure Boot state or kernel (UKI) boot image. That's because in this configuration, the LUKS key is made available by the TPM so long as the system has the expected PCR7 value and the PCR11 policy matches. That default PCR11 policy importantly allows for the TPM to release the key to the booted system rather than just from the initrd part of the signed kernel image (UKI). The attack relies on the attacker being able to substitute the original encrypted root partition for one that they control. By doing so, the system will prompt for a recovery key on boot, which the attacker has defined and can provide, before booting the system using the attacker's root partition rather than the system's original one. The attacker only needs to put a systemd unit starting on system boot within their root partition to have the system run that logic on boot. That unit will then run in an environment where the TPM will allow for the retrieval of the encryption key of the real root disk, allowing the attacker to steal the LUKS volume key (immutable master key) and then use it against the real root disk, altering it or getting data out before putting the disk back the way it was and returning the system without a trace of this attack having happened. This is all possible because the system will have still booted with Secure Boot enabled, will have measured and ran the expected bootloader and kernel image (UKI). The initrd selects the root disk based on GPT partition identifiers making it possible to easily substitute the real root disk for an attacker controlled one. This doesn't lead to any change in the TPM state and therefore allows for retrieval of the LUKS key by the attacker through a boot time systemd unit on their alternative root partition. IncusOS version 202603142010 (2026/03/14 20:10 UTC) includes the new PCR15 logic and will automatically update the TPM policy on boot. Anyone suspecting that their system may have been physically accessed while shut down should perform a full system wipe and reinstallation as only that will rotate the LUKS volume key and prevent subsequent access to the encrypted data should the system have been previously compromised. There are no known workarounds other than updating to a version with corrected logic which will automatically rebind the LUKS keys to the new set of TPM registers and prevent this from being exploited.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-32606 since 03/12/2026. The exploitability is told to be easy. The attack needs to be approached locally. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1552.

Upgrading to version 202603142010 eliminates this vulnerability.

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Productinfo

Vendor

• lxc

Name

• incus-os

Version

• 20260314

Website

• Product: https://github.com/lxc/incus-os/

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