Security readout for executives and security teams
Plain-English summary
This macOS flaw let a malicious application bypass Gatekeeper, Apple’s control for checking downloaded apps. Successful abuse could allow untrusted software to run despite expected protections. Apple and CISA indicate exploitation occurred, so organizations with unpatched Macs should treat this as urgent despite the medium CVSS score.
Executive priority
Prioritize this as a near-term endpoint patching issue. The technical score is medium, but confirmed KEV listing and Gatekeeper bypass potential increase business urgency for Mac-heavy environments.
Technical view
CVE-2021-30657 is a macOS logic issue, mapped to CWE-862, fixed by improved state management. The CVSS vector requires local execution and user interaction, with high integrity impact. Apple fixed it in macOS Big Sur 11.3 and Security Update 2021-002 Catalina.
Likely exposure
Exposure is likely on macOS endpoints running Big Sur before 11.3 or Catalina systems missing Security Update 2021-002. The bundle does not provide a complete version range beyond the fixed releases, so unsupported or unclear macOS builds should be checked against Apple guidance.
Exploitation context
Apple reported possible active exploitation, and CISA lists CVE-2021-30657 in the Known Exploited Vulnerabilities catalog. No exploit mechanics are needed for defense; the key issue is Gatekeeper bypass by a malicious application on an affected Mac.
Researcher notes
The public bundle confirms the vulnerability class, affected platform, fixed Apple releases, CVSS, and exploitation signal. It does not include root-cause detail, exact vulnerable build ranges, indicators of compromise, or a vendor mitigation other than applying Apple updates.
Mitigation direction
- Update Big Sur systems to macOS 11.3 or later.
- Install Security Update 2021-002 on Catalina systems.
- Check Apple security guidance for other affected macOS builds.
- Prioritize remediation for managed Mac fleets and high-risk users.
- Ensure endpoint protection flags suspicious downloaded applications.
Validation and detection
- Inventory macOS versions across managed endpoints.
- Confirm Big Sur hosts are running 11.3 or later.
- Confirm Catalina hosts include Security Update 2021-002.
- Review MDM and EDR telemetry for untrusted app execution.
- Verify CISA KEV tracking includes this CVE in remediation reporting.
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.
CWE-862: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-30657 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
- Medium
- CVSS
- 5.5 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
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.
CISA KEV status
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:N/UI:R/S:U/C:N/I:H/A:N1.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://support.apple.com/en-us/HT212325CVE reference · x_refsource_MISC
- https://support.apple.com/en-us/HT212326CVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30657CVE reference · government-resource
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.
Missing Authorization
Missing Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.