Security readout for executives and security teams
Plain-English summary
This is a Windows information disclosure issue in Event Tracing. A local user with low privileges could potentially access sensitive information. It is not a remote takeover bug, but the confidentiality impact is rated high, so unpatched shared workstations and servers deserve attention.
Executive priority
Schedule remediation through normal Windows patch governance, with faster handling for sensitive multi-user systems. The issue is medium severity, locally exploitable, and confidentiality-focused, with no source evidence of active exploitation.
Technical view
CVE-2021-28435 affects multiple Windows client and server versions. CVSS 3.1 is 5.5: local attack vector, low complexity, low privileges required, no user interaction, unchanged scope, high confidentiality impact, and no integrity or availability impact. The source bundle indicates an official fix is available.
Likely exposure
Exposure is likely limited to Windows systems running the affected versions listed by Microsoft, including Windows 8.1, Windows 10 releases, Windows Server 2012 R2, 2016, 2019, and related Server Core variants, when not updated.
Exploitation context
The bundle does not show CISA KEV listing or active exploitation evidence. The CVSS vector indicates exploitation requires local access and low privileges, with no user interaction. Treat it as a local information disclosure risk rather than an internet-facing remote compromise path.
Researcher notes
Key evidence is the CVSS vector and Microsoft affected-product list. The bundle does not provide root-cause detail, proof-of-concept status, or exploit telemetry. Avoid assuming affected builds beyond Microsoft’s advisory and the CVE record.
Mitigation direction
- Apply the Microsoft security update referenced by the MSRC advisory.
- Prioritize shared servers, jump hosts, and multi-user Windows systems.
- Confirm affected Windows versions are still receiving applicable security updates.
- Check Microsoft guidance for version-specific update requirements.
- Reduce unnecessary local user access on sensitive Windows systems.
Validation and detection
- Inventory Windows hosts against the affected product list.
- Verify installed security updates against the MSRC advisory.
- Use vulnerability scanning to confirm CVE-2021-28435 status.
- Review systems with many local users for higher confidentiality risk.
- Document exceptions where updates cannot be applied promptly.
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-2021-28435 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
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28435CVE 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.