Security readout for executives and security teams
Plain-English summary
CVE-2021-1672 is a Microsoft Windows information disclosure flaw in the Projected File System FS Filter Driver. It requires local low-privileged access, so it is not a direct remote entry point. Business risk is exposure of sensitive information from affected Windows endpoints or servers if an attacker already has a foothold.
Executive priority
Handle through normal patch management, with elevated attention for servers and shared workstations. This is not presented as remotely exploitable or actively exploited in the provided sources, but it can increase damage after local access.
Technical view
The source bundle describes a Windows Projected File System FS Filter Driver information disclosure vulnerability with CVSS 3.1 score 5.5. Attack vector is local, privileges required are low, user interaction is not required, and impact is confidentiality-only with high confidentiality impact. Microsoft lists official remediation availability.
Likely exposure
Exposure is limited to listed Microsoft Windows 10 and Windows Server versions, including 1803, 1809, 1909, 2004, 20H2, and Windows Server 2019/Core variants. Systems with local user access or prior compromise matter most.
Exploitation context
The bundle marks CISA KEV as false and provides no cited evidence of active exploitation. CVSS exploit code maturity is unproven. Treat this mainly as a post-access information disclosure risk unless Microsoft or CISA guidance says otherwise.
Researcher notes
Evidence is sparse beyond Microsoft and CVE metadata. Avoid assuming exploitability beyond local low-privileged access and confidentiality impact. The key research task is confirming affected build presence and Microsoft update applicability, not developing proof-of-concept behavior.
Mitigation direction
- Apply Microsoft security updates for CVE-2021-1672 on affected Windows systems.
- Use the MSRC Update Guide to confirm applicable KBs and fixed builds.
- Prioritize shared endpoints, servers, and systems with many local users.
- Retire or isolate affected systems that cannot receive supported Microsoft updates.
Validation and detection
- Inventory Windows 10 and Windows Server versions against the affected product list.
- Verify installed patch levels against Microsoft’s CVE-2021-1672 guidance.
- Check vulnerability scanner findings for this CVE and confirm OS build evidence.
- Document exceptions for unsupported or unpatchable systems with compensating controls.
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.
CVE-2021-1672 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
- 5.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/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.
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:N/A:N/E:U/RL:O/RC:C1.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- Windows Projected File System FS Filter Driver Information Disclosure VulnerabilityCVE reference · vendor-advisory
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1672CVE reference · x_refsource_MISC, x_transferred
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.