Security readout for executives and security teams
Plain-English summary
This is a Microsoft Visual Studio Installer elevation-of-privilege flaw. An attacker who already has local access with low privileges could potentially gain higher privileges on affected developer machines or build hosts. It is not described as remotely exploitable, but the impact is high because successful exploitation affects confidentiality, integrity, and availability.
Executive priority
Treat this as a high-priority patching item for engineering environments. It is not presented as internet-facing or actively exploited, but it can materially worsen compromise on machines that hold source code, signing tools, or build secrets.
Technical view
CVE-2021-27064 affects listed Microsoft Visual Studio 2017 and 2019 versions. The CVSS 3.1 vector is local, low complexity, low privileges required, no user interaction, unchanged scope, and high confidentiality, integrity, and availability impact. The provided sources do not include CWE, root-cause detail, or fixed version specifics.
Likely exposure
Exposure is most likely on Windows developer workstations, shared engineering desktops, and build agents running the affected Visual Studio 2017 or 2019 version trains listed by Microsoft and CVE records.
Exploitation context
The supplied evidence does not show CISA KEV listing or active exploitation. The CVSS vector indicates local exploitation requiring prior low-privileged access, with proof-of-concept maturity and an official remediation level noted.
Researcher notes
The source bundle is sparse: no CWE, root cause, exploit mechanism, or precise fixed build numbers are provided. Analysis should stay anchored to MSRC and CVE records, with validation focused on affected product inventory and update state.
Mitigation direction
- Apply Microsoft’s official Visual Studio Installer updates for affected Visual Studio versions.
- Prioritize developer workstations and CI/build hosts where local privilege escalation has higher operational impact.
- Restrict local access to shared build machines until patch status is verified.
- Check Microsoft’s advisory for exact fixed versions and deployment guidance.
Validation and detection
- Inventory Visual Studio 2017 and 2019 installations across endpoints and build infrastructure.
- Compare installed versions against the affected version ranges in Microsoft’s advisory.
- Confirm Visual Studio Installer update status through normal enterprise patch reporting.
- Review endpoint telemetry for unusual privilege changes on developer or build systems.
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.
Privilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-27064 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
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/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:H/A:H/E:P/RL:O/RC:C1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-27064CVE 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.