Security readout for executives and security teams
Plain-English summary
CVE-2021-1667 is a high-severity Microsoft Windows RPC Runtime remote code execution flaw. A successful attacker could run code on affected Windows systems, with major confidentiality, integrity, and availability impact. The source bundle indicates low attack complexity, network reachability, low privileges required, and no user interaction.
Executive priority
Treat this as a patch-priority Windows platform issue, especially for servers and legacy systems. No active exploitation is evidenced here, but the technical impact is severe enough to require timely remediation tracking.
Technical view
The CVSS 3.1 vector is 8.8: network attack vector, low complexity, low privileges, no user interaction, unchanged scope, and high C/I/A impact. Affected products include multiple Windows client and server releases from Windows 7/Server 2008 SP2 through Windows 10/Server 20H2.
Likely exposure
Exposure is likely where listed Windows versions remain unpatched and reachable over networks that allow RPC access. The bundle does not identify a specific vulnerable RPC interface, port, service configuration, or exposed internet footprint.
Exploitation context
The bundle marks KEV as false and CVSS exploit code maturity as unproven. There is no supplied evidence of active exploitation. Risk remains material because exploitation is network-based, low-complexity, and does not require user interaction.
Researcher notes
The available sources provide severity, affected platforms, CVSS, and Microsoft advisory links, but not root-cause details, vulnerable RPC interfaces, indicators, or standalone mitigations. Validation should stay focused on asset matching and Microsoft patch state.
Mitigation direction
- Apply Microsoft security updates for CVE-2021-1667 on all affected Windows systems.
- Use the MSRC advisory to confirm exact update packages for each OS version.
- Prioritize servers, domain infrastructure, and systems reachable from less-trusted networks.
- Retire, isolate, or formally risk-accept systems that cannot receive applicable updates.
- Avoid relying on undocumented workarounds not provided by Microsoft.
Validation and detection
- Inventory Windows versions against the affected product list in the bundle.
- Verify installed Microsoft updates correspond to CVE-2021-1667 remediation guidance.
- Confirm legacy Windows 7 and Server 2008 systems are patched, isolated, or retired.
- Review network segmentation around systems requiring RPC exposure.
- Document any unpatched exceptions with owner, business reason, and 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.
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-2021-1667 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
- Remote Procedure Call Runtime Remote Code Execution VulnerabilityCVE reference · vendor-advisory
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1667CVE 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.