Security readout for executives and security teams
Plain-English summary
CVE-2021-27096 is a Windows NTFS privilege escalation vulnerability. An attacker who already has low-privileged local access could potentially gain greater control of an affected Windows system. The business risk is mainly post-compromise escalation on unpatched endpoints or servers.
Executive priority
Prioritize in normal high-severity patch cycles, with faster handling for critical servers and privileged workstations. The issue is not described as remotely exploitable or actively exploited, but it can increase impact after an attacker gains local access.
Technical view
The supplied CVSS 3.1 vector is 7.8 high: local attack, low complexity, low privileges required, no user interaction, unchanged scope, and high confidentiality, integrity, and availability impact. Microsoft lists affected Windows client and server versions, with official remediation indicated in the CVSS metadata.
Likely exposure
Exposure is likely where affected Windows 7, 8.1, Windows 10, or Windows Server 2008 R2 through 20H2 systems remain unpatched or unsupported. Internet exposure is not implied because the attack vector is local.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. CVSS exploit maturity is listed as unproven. Treat this as a serious local escalation risk, especially after phishing, malware execution, or compromised user access.
Researcher notes
Public details in the bundle are sparse: no CWE, root cause, exploit narrative, or KB identifiers are provided. Analysis should stay anchored to Microsoft and CVE data: NTFS EoP, local vector, low privilege required, high impact, and official remediation availability.
Mitigation direction
- Apply the relevant Microsoft security updates for affected Windows versions.
- Prioritize servers, administrator workstations, and high-value user endpoints.
- Retire or isolate unsupported Windows systems where updates are unavailable.
- Use least privilege to reduce local account misuse before patching completes.
Validation and detection
- Inventory Windows versions against the affected product list in the source bundle.
- Confirm patch compliance through Microsoft update tooling or vulnerability management data.
- Verify unsupported Windows hosts have compensating controls or retirement plans.
- Check scanner findings specifically reference CVE-2021-27096 and affected OS builds.
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.
Privilege 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-2021-27096 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.
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:C1.85.9Primary CVE scoreVulnerability 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
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-27096CVE reference · x_refsource_MISC
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.