Security readout for executives and security teams
Plain-English summary
This is a Microsoft Secure Boot bypass that could expose sensitive information on affected Windows systems. The score is medium because exploitation requires physical access, but the impact is meaningful where devices contain protected data or depend on Secure Boot for trust.
Executive priority
Treat as a scheduled security update priority, not an emergency, unless sensitive Windows devices are physically exposed or patch coverage is weak.
Technical view
CVE-2025-21215 is a Secure Boot security feature bypass associated with CWE-125. The CVSS 3.1 vector is AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N, meaning physical access is required and confidentiality impact is high. Microsoft lists an official remediation.
Likely exposure
Exposure is limited to Microsoft-listed Windows 10, Windows 11, and Windows Server releases, including older Server 2008 through Server 2019 versions. Highest concern is laptops, kiosks, shared workstations, and physically reachable servers.
Exploitation context
The provided bundle does not show CISA KEV listing or confirmed active exploitation. The CVSS vector indicates an attacker needs physical access, with no privileges or user interaction required.
Researcher notes
Evidence is limited to CVE and Microsoft advisory metadata. Do not assume remote exploitation. Focus validation on affected builds, Secure Boot reliance, physical access paths, and update applicability.
Mitigation direction
- Apply Microsoft-provided security updates for affected Windows releases.
- Use the MSRC advisory to identify the correct update for each version.
- Prioritize mobile, shared, and physically exposed systems.
- Maintain physical access controls for sensitive endpoints and servers.
- Track Microsoft guidance for any Secure Boot-specific follow-up actions.
Validation and detection
- Inventory systems against the affected Windows versions and build numbers.
- Verify installed update status against the MSRC advisory.
- Confirm high-risk devices are covered by endpoint management reporting.
- Check whether physically exposed systems have compensating access controls.
- Monitor CVE and MSRC records for revised guidance.
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-125: 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 lookupCVE-2025-21215 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
- Medium
- CVSS
- 4.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/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:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C0.93.6microsoftVulnerability scoring details
Base CVSS 3.1 score
4.6MediumVector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/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
- Secure Boot Security Feature Bypass 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.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.