Security readout for executives and security teams
Plain-English summary
CVE-2025-21213 is a Microsoft Secure Boot security feature bypass. An attacker with physical access could bypass a boot-time protection and gain access to confidential data. Microsoft rates it medium severity and lists official remediation as available. There is no provided evidence of active exploitation.
Executive priority
Schedule remediation through standard Windows patching, with faster handling for devices at higher physical-access risk. This is not a top emergency based on available evidence, but it weakens a foundational boot security control and should not be deferred indefinitely.
Technical view
The CVSS 3.1 vector is 4.6: AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. The issue is mapped to CWE-284 and affects multiple supported Windows client and server versions. The impact is confidentiality only, with no integrity or availability impact stated in the provided data.
Likely exposure
Exposure is mainly Windows endpoints and servers in the listed affected versions where Secure Boot protections matter and updates have not been applied. The physical-access requirement lowers broad remote risk but raises concern for laptops, kiosks, labs, branch offices, and less-controlled server rooms.
Exploitation context
The source data indicates physical access is required, with low attack complexity, no privileges, and no user interaction. CISA KEV status is false in the bundle, and no cited source claims active exploitation. Treat this as a local physical-access risk, not an internet-exposed remote vulnerability.
Researcher notes
Evidence is limited to the CVE record, CVE List data, and Microsoft advisory metadata. The bundle does not include technical root cause details, proof-of-concept status, or specific KB numbers. Avoid assuming exploitability beyond the CVSS physical-access model and Microsoft’s security feature bypass classification.
Mitigation direction
- Apply Microsoft updates for CVE-2025-21213 from the MSRC guidance.
- Prioritize mobile, shared, kiosk, and physically accessible systems.
- Confirm affected Windows versions are covered by normal patch management.
- Review Microsoft’s advisory for any product-specific update details.
Validation and detection
- Inventory Windows versions listed in the advisory.
- Check patch compliance against Microsoft guidance for CVE-2025-21213.
- Verify Secure Boot is enabled where required by policy.
- Confirm no high-risk devices remain unpatched after deployment.
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-284: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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-2025-21213 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.
Improper Access Control
Improper Access Control represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.