Security readout for executives and security teams
Plain-English summary
This flaw could let someone who already has local access to an affected Windows machine read sensitive information through the TPM device driver. It is not a remote takeover issue, but it matters on shared systems, workstations with untrusted users, and servers where low-privileged access may already exist.
Executive priority
Treat as a normal patch-management priority unless the environment has many shared Windows systems or known local account compromise. It has meaningful confidentiality impact, but the source evidence does not support emergency handling or internet-facing exposure.
Technical view
CVE-2021-1656 is an information disclosure flaw in Microsoft’s TPM device driver affecting listed Windows client and server releases. CVSS 3.1 is 5.5: local attack vector, low complexity, low privileges required, no user interaction, and high confidentiality impact only. The bundle indicates official remediation is available.
Likely exposure
Exposure is most likely on affected Windows endpoints and servers from Windows 7/Server 2008 R2 through Windows 10/Server 2019 and SAC releases listed by Microsoft. Risk depends on patch status and whether attackers can obtain local low-privileged access.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. The CVSS vector requires local access and low privileges, so this is more relevant for post-compromise data exposure or multi-user systems than internet-facing initial access.
Researcher notes
Do not assume remote exploitability. Validate OS version and patch level first, then map findings to Microsoft’s affected-product list. The public bundle gives limited technical detail beyond TPM device driver information disclosure, so deeper root-cause claims would require additional vendor or reverse-engineering evidence.
Mitigation direction
- Apply the relevant Microsoft security update from the MSRC advisory.
- Prioritize shared endpoints, jump hosts, and servers with interactive user access.
- Check Microsoft guidance for exact update applicability by Windows version.
- Reduce unnecessary local user access on affected systems until patched.
Validation and detection
- Inventory Windows versions against the affected product list.
- Confirm January 2021 or later applicable security updates are installed.
- Review vulnerability scanner results for CVE-2021-1656 findings.
- Check exception lists for legacy Windows systems still in service.
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-2021-1656 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
- TPM Device Driver Information Disclosure VulnerabilityCVE reference · vendor-advisory
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1656CVE 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.