Security readout for executives and security teams
Plain-English summary
CVE-2021-1660 is a high-severity Microsoft Windows Remote Procedure Call Runtime flaw that could allow remote code execution. The business risk is serious because successful compromise could affect confidentiality, integrity, and availability on Windows endpoints and servers. The available sources do not show confirmed active exploitation.
Executive priority
Treat as a high-priority patching issue for Windows fleets, especially servers and legacy systems. There is no evidence of active exploitation in the provided sources, but the impact rating justifies timely remediation.
Technical view
Microsoft describes this as a Remote Procedure Call Runtime remote code execution vulnerability. CVSS 3.1 score is 8.8 with network attack vector, low complexity, low privileges required, no user interaction, unchanged scope, and high impact to confidentiality, integrity, and availability.
Likely exposure
Exposure is most likely on unpatched affected Windows client and server versions, including Windows 7, 8.1, Windows 10 releases, and Windows Server 2008 through 2019 variants listed in the source bundle.
Exploitation context
The source bundle marks KEV as false and CVSS exploit maturity as unproven. No cited source in the bundle confirms active exploitation or public exploit availability, so treat exploitation status as not evidenced here.
Researcher notes
The bundle provides severity, affected products, CVSS vector, and Microsoft advisory links, but no CWE, root cause detail, or exploit narrative. Avoid assuming exploitability beyond the CVSS vector and Microsoft RCE classification.
Mitigation direction
- Apply the applicable Microsoft security update from the MSRC advisory.
- Prioritize servers and endpoints where RPC is reachable by low-privileged users.
- Upgrade or retire unsupported affected Windows versions where updates are unavailable.
- Limit unnecessary network access to RPC services through segmentation and firewall policy.
- Check Microsoft guidance for any version-specific remediation requirements.
Validation and detection
- Inventory Windows versions against the affected product list in the source bundle.
- Confirm installed patches match Microsoft guidance for CVE-2021-1660.
- Identify systems still running unsupported Windows releases listed as affected.
- Review network paths where low-privileged users can reach RPC services.
- Track exceptions with owner, business justification, 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-2021-1660 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-2021-1660CVE 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.