Security readout for executives and security teams
Plain-English summary
A flaw in Windows VBS Enclave handling could let a signed-in attacker with limited permissions gain higher privileges on an affected computer. Exploitation is local, requires no user interaction, and could expose, alter, or disrupt system data and services.
Executive priority
Treat this as a high-priority patching issue, not an unauthenticated emergency. Accelerate remediation where many users share systems or local access is broadly granted. Standard endpoint fleets should receive the applicable Microsoft update through the normal expedited security-update process.
Technical view
CVE-2026-20938 is a CWE-822 untrusted pointer dereference in Windows Virtualization-Based Security Enclave. Microsoft rates the local attack as low complexity, requiring low privileges and no user interaction. The CVSS 3.1 score is 7.8, with high confidentiality, integrity, and availability impact.
Likely exposure
The supplied record lists Windows 11 23H2, 24H2, and 25H2 builds as affected. Prioritize systems running these releases, particularly shared endpoints or devices where untrusted users can obtain local accounts. The bundle does not establish whether every listed installation enables or uses VBS Enclave functionality.
Exploitation context
The attacker must already have authorized local access with low privileges. The vulnerability is not listed as known exploited in the supplied KEV signal, and the CVSS vector marks exploit maturity as unproven. No evidence in the bundle supports active exploitation or remote, unauthenticated compromise.
Researcher notes
The record identifies an untrusted pointer dereference but provides no detailed vulnerable code path, enclave configuration requirement, public proof of concept, or detection indicators. The CVSS vector reports local access, low complexity, low privileges, no user interaction, unchanged scope, and high impact across confidentiality, integrity, and availability.
Mitigation direction
- Review Microsoft’s CVE advisory and deploy its applicable security update.
- Prioritize affected shared systems and endpoints accessible to lower-trust local users.
- Restrict unnecessary local accounts and interactive access while remediation is pending.
- Follow subsequent Microsoft guidance for any prerequisites or additional mitigations.
Validation and detection
- Inventory Windows 11 release and build information across managed endpoints.
- Compare installed update status with Microsoft’s CVE advisory.
- Confirm applicable security updates installed successfully and devices completed any required restart.
- Review affected systems for unexpected privilege changes or suspicious local account activity.
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-822: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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 lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-20938 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 Virtualization-Based Security (VBS) Enclave Elevation of Privilege 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.
Untrusted Pointer Dereference
Untrusted Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.