Security readout for executives and security teams
Plain-English summary
This affects Microsoft Windows System Image Manager in the ADK, a tool used by IT teams to build and deploy Windows images. A logged-in attacker could abuse unsafe deserialization to run code on the local system. The issue is high severity, but the provided evidence does not show internet-remote or active exploitation.
Executive priority
Handle as a high-priority endpoint and deployment-tooling patch. It is not described as remotely exploitable over the internet, but compromise of ADK systems could affect privileged Windows deployment workflows and sensitive image-building environments.
Technical view
CVE-2026-25166 is CWE-502 deserialization of untrusted data in Windows SIM. Microsoft rates it CVSS 3.1 7.8 with AV:L/AC:L/PR:L/UI:N/S:U and high confidentiality, integrity, and availability impact. Affected entries include Windows ADK for Windows 10 2004, Windows 11 22H2/23H2/24H2, and Windows Server 2022.
Likely exposure
Most exposure is likely on administrator workstations, deployment servers, build systems, and imaging environments where Microsoft Windows ADK and Windows System Image Manager are installed. Ordinary Windows endpoints without ADK are not identified as affected in the provided sources.
Exploitation context
The source bundle says exploitation requires an authorized local attacker with low privileges and no user interaction. KEV status is false, and no cited source in the bundle reports active exploitation. Public details are limited, so treat exploitability specifics as unconfirmed beyond Microsoft’s CVSS assessment.
Researcher notes
Evidence is limited to Microsoft/CVE metadata in the supplied bundle. The sources do not provide trigger format, vulnerable component internals, proof-of-concept status, or detailed fix mechanics. Avoid assuming broader Windows OS exposure without confirming ADK/Windows SIM presence.
Mitigation direction
- Apply Microsoft’s update or remediation guidance for affected Windows ADK versions.
- Prioritize ADK installations on deployment, build, and administrator systems.
- Restrict local access to systems that run Windows System Image Manager.
- Review vendor guidance before using compensating controls as a substitute for patching.
Validation and detection
- Inventory systems with Windows ADK or Windows System Image Manager installed.
- Map installed ADK versions to the affected Microsoft product list.
- Confirm Microsoft’s relevant update or remediation has been applied.
- Check EDR and local logs for suspicious activity on ADK administrator systems.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-502: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-25166 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C1.85.9microsoftVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- Windows System Image Manager Assessment and Deployment Kit (ADK) Remote Code Execution VulnerabilityCVE reference, microsoft · vendor-advisory, patch
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Deserialization of Untrusted Data
Deserialization of Untrusted Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.