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Constellation has insecure LUKS2 persistent storage partitions which may be opened and used

High severity GitHub Reviewed Published Oct 27, 2025 in edgelesssys/constellation • Updated Oct 27, 2025

Package

gomod github.com/edgelesssys/constellation/v2 (Go)

Affected versions

<= 2.23.1

Patched versions

2.24.0

Description

Summary

A malicious host may provide a crafted LUKS2 volume to a confidential computing guest that is using the OpenCryptDevice feature. The guest will open the volume and write secret data using a volume key known to the attacker. The attacker can also pre-load data on the device, which could potentially compromise guest execution.

LUKS2 volume metadata is not authenticated and supports null key-encryption algorithms, allowing an attacker to create a volume such that the volume:

  • Opens (cryptsetup open) without error using any passphrase or token
  • Records all writes in plaintext (or ciphertext with an attacker-known key)
  • Contains arbitrary data chosen by the attacker

Details

The Constellation CVM image uses LUKS2-encrypted volumes for persistent storage. When opening an encrypted storage device, the CVM uses the libcryptsetup function crypt_activate_by_passhrase. If the VM is successful in opening the partition with the disk encryption key, it treats the volume as confidential. However, due to the unsafe handling of null keyslot algorithms in the cryptsetup 2.8.1, it is possible that the opened volume is not encrypted at all.

Cryptsetup prior to version 2.8.1 does not report an error when processing LUKS2-formatted disks that use the cipher_null-ecb algorithm in the keyslot encryption field.

Impact

A LUKS2 disk encrypted with a master key, which is in turn encrypted with user passwords stored in some number of keyslots. By creating a malicious disk which sets the keyslot encryption algorithm to ”crypto_null-ecb”, an attacker can construct a disk such that keyslot decryption does not depend in any way on the enclave-held secret data. When a confidential guest opens such a device using cryptsetup open, the mapped disk is created without error, and any further writes to the disk are encrypted using an attacker-controlled key.

Patches

To protect against this and similar attacks, Constellation now performs detached reading of LUKS headers. The header is copied into the encrypted memory of the CVM and then verified. The verified header is then used to open the encrypted LUKS device in detached header mode. This was implemented in edgelesssys/constellation#3927 and release as part of Constellation v2.24.0.

References

@katexochen katexochen published to edgelesssys/constellation Oct 27, 2025
Published to the GitHub Advisory Database Oct 27, 2025
Reviewed Oct 27, 2025
Published by the National Vulnerability Database Oct 27, 2025
Last updated Oct 27, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Local
Attack Complexity Low
Attack Requirements None
Privileges Required High
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability None
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS score

Weaknesses

Improper Verification of Cryptographic Signature

The product does not verify, or incorrectly verifies, the cryptographic signature for data. Learn more on MITRE.

Files or Directories Accessible to External Parties

The product makes files or directories accessible to unauthorized actors, even though they should not be. Learn more on MITRE.

CVE ID

CVE-2025-58356

GHSA ID

GHSA-hq76-6gh2-5g4q

Source code

Credits

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