Security Resilience

CVE-2026-23655

Microsoft Confidential Sidecar Containers ≤ 2.12

Published
10 February 2026
Modified
25 February 2026
Patch / advisory
View advisory
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.010 63th percentile
Risk Priority 52 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-23655 is a medium-severity Cleartext Storage of Sensitive Information (CWE-312) vulnerability in Microsoft Confidential Sidecar Containers. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Steal Web Session Cookie (T1539); ranked in the top 37% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SC-28 (Protection of Information at Rest) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A06:2025 Insecure Design

EU & UK References

Vulnerability Data

Cleartext storage of sensitive information in Azure Compute Gallery allows an authorized attacker to disclose information over a network.

CWE(s)
CWE-312

Related Threats

MITRE ATT&CK Enterprise Techniques

T1539 Steal Web Session Cookie Credential Access
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials.
attack.mitre.org →
T1552.006 Group Policy Preferences Credential Access
Adversaries may attempt to find unsecured credentials in Group Policy Preferences (GPP).
attack.mitre.org →
T1555.002 Securityd Memory Credential Access
An adversary with root access may gather credentials by reading `securityd`’s memory.
attack.mitre.org →
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
T1552 Unsecured Credentials Credential Access
Adversaries may search compromised systems to find and obtain insecurely stored credentials.
attack.mitre.org →
T1552.001 Credentials In Files Credential Access
Adversaries may search local file systems and remote file shares for files containing insecurely stored credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-49728Same vendor: Microsoft
CVE-2025-55334Same vendor: Microsoft
CVE-2023-28345Same vendor: Microsoft
CVE-2024-35117Same vendor: Microsoft
CVE-2023-24964Same vendor: Microsoft
CVE-2023-22878Same vendor: Microsoft
CVE-2023-44159Same vendor: Microsoft
CVE-2025-63208Shared CWE-312
CVE-2024-46340Shared CWE-312
CVE-2023-22949Shared CWE-312

Affected Assets

microsoft
confidential sidecar containers
≤ 2.12

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 4 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V14.2.8

Mitigating Controls (NIST 800-53 r5) AI

SC-28 Protection of Information at Rest good match

SC-28 requires cryptographic or equivalent protection of sensitive data at rest, directly stopping cleartext storage in accessible resources.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.DS-01 full match
blocks

Encryption and cryptographic controls for data-at-rest directly prevent cleartext storage of sensitive information.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.24 Use of cryptography full match
removes

created from the owner's anchor; an owner grade is a row and does not wait for an instrument (Mythos 2026-09-29T15:58Z).

A.8.12 Data leakage prevention partial match
finds

When clear-text sensitive data is detected leaving controlled storage, the control can block the transfer, thereby limiting the exposure that would result from unencrypted storage on external media or cloud services.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248525 All OL 8 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at-rest protection. blocks CWE-312
Oracle Linux 9 (1 rule)
  • V-271756 OL 9 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at rest protection. blocks CWE-312
RHEL 8 (1 rule)
  • V-230224 All RHEL 8 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at rest protection. blocks CWE-312

References