Summary
Constellation has insecure LUKS2 persistent storage partitions which may be opened and used
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.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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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 https://github.com/edgelesssys/constellation/pull/3927 and release as part of Constellation v2.24.0.
Frequently Asked Questions
- What is CVE-2025-58356? CVE-2025-58356 is a high-severity security vulnerability in github.com/edgelesssys/constellation/v2 (go), affecting versions <= 2.23.1. It is fixed in 2.24.0.
- Which versions of github.com/edgelesssys/constellation/v2 are affected by CVE-2025-58356? github.com/edgelesssys/constellation/v2 (go) versions <= 2.23.1 is affected.
- Is there a fix for CVE-2025-58356? Yes. CVE-2025-58356 is fixed in 2.24.0. Upgrade to this version or later.
- Is CVE-2025-58356 exploitable, and should I be worried? Whether CVE-2025-58356 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-58356 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-58356? Upgrade
github.com/edgelesssys/constellation/v2to 2.24.0 or later.