CVE-2026-23655 identifies a vulnerability classified under CWE-312, which involves the cleartext storage of sensitive information in Microsoft ACI Confidential Containers, specifically within the Azure Compute Gallery. The vulnerability affects version 1.0.0 of the product and was published on February 10, 2026. The core issue is that sensitive data, which should be protected through encryption or other secure storage mechanisms, is instead stored in an unencrypted form. This flaw allows an attacker who already has authorized access and network connectivity to the affected environment to retrieve sensitive information by intercepting or accessing this data in transit or at rest. The CVSS v3.1 base score is 6.5, indicating a medium severity level. The vector string (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N) shows that the attack can be conducted remotely over the network with low complexity, requires privileges but no user interaction, and results in a high impact on confidentiality without affecting integrity or availability. Although no known exploits are currently reported in the wild, the vulnerability poses a significant risk to confidentiality, especially in environments handling sensitive or regulated data. The lack of patch links suggests that a fix may not yet be publicly available, emphasizing the need for interim mitigations. The vulnerability is particularly relevant for organizations leveraging Microsoft’s confidential container technology in Azure for secure workload deployment, as it undermines the confidentiality guarantees expected from such solutions.

For European organizations, the impact of CVE-2026-23655 is primarily on the confidentiality of sensitive information stored or processed within Microsoft ACI Confidential Containers. Unauthorized disclosure of sensitive data could lead to regulatory non-compliance, especially under GDPR, resulting in legal penalties and reputational damage. Organizations in sectors such as finance, healthcare, and government, which often use confidential computing to protect sensitive workloads, are at heightened risk. The vulnerability could facilitate data breaches, espionage, or insider threats if attackers leverage authorized access to extract cleartext data. Since the vulnerability does not affect integrity or availability, operational disruption is unlikely, but the exposure of confidential data could have long-term strategic consequences. The medium severity rating reflects the balance between the need for privileges and the significant confidentiality impact. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits once the vulnerability becomes widely known.

To mitigate CVE-2026-23655, European organizations should implement several targeted measures beyond generic advice: 1) Encrypt sensitive data at rest within Azure Compute Gallery and ensure that any stored secrets or credentials are protected using Azure Key Vault or equivalent hardware security modules. 2) Enforce strict network segmentation and access controls to limit which users and services have authorized access to the ACI Confidential Containers environment, minimizing the attack surface. 3) Implement robust monitoring and logging of access to the Azure Compute Gallery and container environments to detect anomalous or unauthorized data access attempts promptly. 4) Apply the principle of least privilege rigorously, ensuring that users and services have only the minimum necessary permissions to operate. 5) Stay informed on Microsoft’s security advisories for patches or updates addressing this vulnerability and plan for timely deployment once available. 6) Consider additional encryption or tokenization of sensitive data before it is stored or processed in the affected environment as a compensating control. 7) Conduct regular security assessments and penetration testing focused on container environments to identify and remediate similar misconfigurations or vulnerabilities.