Security readout for executives and security teams
Plain-English summary
CVE-2021-33773 is a Windows privilege-escalation issue in Remote Access Connection Manager. An attacker who already has low-privileged local access could potentially gain higher privileges on affected Windows endpoints or servers. It is not described as remotely exploitable from the internet in the provided sources.
Executive priority
Treat as high priority, especially for Windows servers and shared endpoints. This is not evidenced as actively exploited in the provided sources, but it can turn an existing foothold into full system control if unpatched.
Technical view
The CVSS 3.1 vector is AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, score 7.8. Microsoft lists affected Windows 8.1, Windows 10, and Windows Server 2012 R2, 2016, 2019, 2004, and 20H2 builds. The temporal vector indicates an official fix exists and exploit maturity is unproven.
Likely exposure
Exposure is likely where affected Windows desktop or server versions remain unpatched. Risk is highest on shared workstations, terminal servers, jump hosts, and servers where low-privileged users or compromised accounts can execute locally.
Exploitation context
The source bundle does not show CISA KEV listing or cited active exploitation. Exploitation requires local low-privileged access and no user interaction, making it relevant as a post-compromise privilege-escalation path rather than an initial internet-facing entry point.
Researcher notes
The public data gives product scope, CVSS, and official-fix status, but not root-cause detail or exploit technique. Avoid assuming Remote Access Connection Manager service configuration alone proves exposure; validate by OS build and patch state.
Mitigation direction
- Apply Microsoft’s official security update for CVE-2021-33773.
- Check MSRC guidance for supported update packages and supersedence.
- Prioritize shared systems and servers with local user access.
- Reduce unnecessary local logon rights until patching is confirmed.
- Retire or isolate unsupported affected Windows versions.
Validation and detection
- Inventory Windows versions against the affected product list.
- Confirm installed build levels include Microsoft’s fix.
- Check vulnerability scanner results for CVE-2021-33773 closure.
- Review shared servers for low-privileged local access paths.
- Document exceptions and compensating controls for unpatched assets.
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-2021-33773 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: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:H/A:H/E:U/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:U/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33773CVE 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.