CVE-2025-71424
Received Received - Intake

Arbitrary File Write in Contrast Kubernetes Runtime

Publication date: 2026-09-27

Last updated on: 2026-09-27

Assigner: VulnCheck

Description
Contrast, Edgeless Systems' runtime for confidential containers on Kubernetes, is affected in versions up to and including 1.9.0. The VOLUME directive in a Dockerfile (config.volumes in the OCI image configuration) is only a hint and is not handled specially by Kubernetes, but containerd adds a mount point for it when Kubernetes sets none, requiring the runtime to be able to push arbitrary data to the Kata agent. As a result, on bare-metal Contrast deployments (AKS deployments are not affected) that run an image declaring at least one VOLUME for which no Kubernetes mount exists at that path, the untrusted host can write arbitrary file trees below that mount point inside the confidential container, compromising the integrity of a directory that is typically important to the application's core functionality. Version 1.9.1 fixes the issue by disallowing this configuration in `contrast generate`.

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Meta Information

Published
2026-09-27
Last Modified
2026-09-27
Generated
2026-09-27
AI Q&A
2026-09-27
EPSS Evaluated
N/A
NVD
CVE-2025-71424
EUVD
EUVD-2025-211008

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
edgeless_systems contrast to 1.9.0 (inc)
edgeless_systems contrast 1.9.1
edgeless_systems contrast From 0 (inc) to 1.9.1 (exc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-693 The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.

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Executive Summary

CVE-2025-71424 affects Contrast runtime for confidential containers on Kubernetes up to version 1.9.0. The VOLUME directive in Dockerfiles or OCI images can create mount points that Kubernetes does not manage, but containerd may populate with untrusted host data. On bare-metal deployments (not AKS), this allows the host to write arbitrary files into the container at the mount point, compromising application integrity.

Detection Guidance

Check Contrast runtime versions with: kubectl get pods -n <namespace> -o jsonpath='{.items[*].spec.containers[?(@.image)].image}' | grep contrast. Verify if any images declare VOLUME directives without Kubernetes mounts. Inspect containerd logs for unexpected mount points: journalctl -u containerd -n 100 --no-pager | grep -i volume.

Impact Analysis

An attacker with access to the host system could write malicious files into a confidential container, potentially altering application behavior or stealing sensitive data. This affects bare-metal Contrast deployments where images declare VOLUME directives without Kubernetes mounts at those paths.

Compliance Impact

This vulnerability primarily impacts data integrity within confidential containers. While it does not directly expose confidential data, it allows unauthorized modifications to application directories, which could undermine compliance with integrity-focused controls in standards like GDPR (Article 32) and HIPAA (Security Rule). However, the vulnerability does not directly lead to data breaches or unauthorized access, so its impact on compliance is likely secondary and depends on specific implementation contexts.

Mitigation Strategies

Upgrade Contrast to version 1.9.1 or later. As a workaround, add emptyDir mounts to VOLUME paths or remove config.volumes entries from images. For bare-metal deployments, ensure no VOLUME directives exist without corresponding Kubernetes mounts.

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