Security readout for executives and security teams
Plain-English summary
This macOS issue could let someone who already has screen sharing access see a different user's screen. The business risk is unintended exposure of sensitive work sessions, documents, chats, or credentials visible on screen. Apple says the issue was fixed by improved state management in macOS Big Sur 11.0.1.
Executive priority
Treat this as a targeted privacy and data-exposure issue, not a confirmed mass-exploitation emergency. Prioritize shared Macs, administrator workstations, support-managed systems, and any environment where screen sharing is enabled for sensitive users or regulated data.
Technical view
CVE-2020-27893 is a screen sharing state-management flaw in macOS. Apple describes the impact as a user with screen sharing access being able to view another user's screen. The public sources do not provide CVSS, CWE, exact affected version ranges, or deeper technical root-cause detail.
Likely exposure
Exposure is most likely on macOS systems running versions before macOS Big Sur 11.0.1 where Screen Sharing or related remote access is enabled. The provided sources do not enumerate all affected macOS releases, so asset validation should focus on version and screen sharing configuration.
Exploitation context
The source bundle does not show CISA KEV listing or other evidence of active exploitation. The stated prerequisite is existing screen sharing access, which limits broad internet-scale abuse but still matters in shared, admin, support, or compromised-account scenarios.
Researcher notes
Public detail is sparse. Apple attributes the fix to improved state management and only states the impact condition. No exploit mechanics, CVSS vector, CWE, or complete affected-version matrix is available in the supplied sources, so avoid assumptions beyond screen sharing access and macOS before the fixed release.
Mitigation direction
- Update affected macOS systems to Big Sur 11.0.1 or a later supported release.
- Restrict screen sharing access to approved administrators and support personnel only.
- Disable screen sharing on endpoints where it is not operationally required.
- Review Apple security guidance for any environment-specific remediation details.
Validation and detection
- Inventory macOS endpoints and record exact operating system versions.
- Identify systems with Screen Sharing or remote management enabled.
- Review users and groups allowed to access screen sharing.
- Confirm exposed systems are updated to macOS Big Sur 11.0.1 or later.
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.
CVE-2020-27893 mapping review
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Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://support.apple.com/en-us/HT211931CVE 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.