Security readout for executives and security teams
Plain-English summary
CVE-2021-28333 is a high-severity Microsoft Windows Remote Procedure Call Runtime flaw that could allow remote code execution. It affects many Windows client and server releases, including legacy versions. The supplied data shows attacker privileges are required, but user interaction is not.
Executive priority
Treat this as high priority for normal patch management, with extra urgency for servers, exposed Windows assets, and unsupported operating systems. The evidence does not justify emergency active-exploitation language.
Technical view
The CVSS 3.1 vector is 8.8 high: network attack vector, low complexity, low privileges required, no user interaction, unchanged scope, and high confidentiality, integrity, and availability impact. The source bundle identifies the component as Microsoft RPC Runtime and lists official Microsoft guidance.
Likely exposure
Organizations with affected Windows desktops or servers from Windows 7/Server 2008 through Windows 10/Server 20H2 may be exposed, especially where legacy or unpatched systems remain in service.
Exploitation context
The supplied data does not show CISA KEV listing or cited evidence of active exploitation. It also does not provide exploit mechanics. Treat as a serious patching issue because network reachability and low attack complexity are indicated.
Researcher notes
The bundle is sparse: no CWE, root-cause detail, or exploit description is provided. Some CPE mappings appear broad or duplicated, so validate product applicability against Microsoft’s advisory and actual installed build levels.
Mitigation direction
- Apply the Microsoft security update referenced by the MSRC advisory.
- Prioritize internet-exposed, server, and legacy Windows systems first.
- Review unsupported Windows versions for isolation or upgrade paths.
- Confirm compensating controls against unnecessary RPC exposure.
- Track remediation exceptions with business owner and retirement date.
Validation and detection
- Inventory Windows versions against the affected product list.
- Confirm April 2021 or later applicable Microsoft security updates are installed.
- Review vulnerability scanner findings for CVE-2021-28333 coverage.
- Validate legacy Windows systems separately because support status may vary.
- Document any systems that cannot be patched immediately.
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.
Execution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-28333 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
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/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:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/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-2021-28333CVE 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.