Security readout for executives and security teams
Plain-English summary
This Apple macOS issue is a buffer overflow that could let a malicious application run code with kernel privileges. That means compromise could move from an app-level problem to deep operating-system control. Apple fixed it in Monterey 12.1, Big Sur 11.6.2, and Security Update 2021-008 for Catalina.
Executive priority
Treat this as a high-priority endpoint patching item, especially for fleets with older macOS systems. Kernel-level code execution can materially increase the impact of malware already running on a device, even without evidence of active exploitation in the provided sources.
Technical view
CVE-2021-30977 is described as a macOS buffer overflow resolved through improved bounds checking. The stated impact is arbitrary code execution with kernel privileges by a malicious application. The source bundle does not provide CVSS, CWE, affected version ranges, exploit details, or a named vulnerable component.
Likely exposure
Exposure is likely limited to Apple macOS systems older than the fixed releases, but the exact affected version range is not provided. Prioritize Macs that can run local applications and are missing Monterey 12.1, Big Sur 11.6.2, or Catalina Security Update 2021-008.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. The stated attack context is a malicious application, so this is not evidenced as a remote unauthenticated network exploit in the bundle.
Researcher notes
Evidence is sparse. Apple names the vulnerability class, impact, and fixed releases, but not the vulnerable component, affected build range, root cause details, or exploitation prerequisites beyond a malicious application. Do not assume active exploitation or remote reachability from this bundle.
Mitigation direction
- Update macOS Monterey systems to 12.1 or later.
- Update macOS Big Sur systems to 11.6.2 or later.
- Apply Security Update 2021-008 on supported Catalina systems.
- Check Apple guidance for unsupported or unclear macOS upgrade paths.
- Limit execution of untrusted macOS applications until patched.
Validation and detection
- Inventory macOS versions across managed endpoints.
- Verify Monterey devices report version 12.1 or later.
- Verify Big Sur devices report version 11.6.2 or later.
- Verify Catalina devices have Security Update 2021-008 installed.
- Review MDM or EDR coverage for outdated macOS devices.
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-2021-30977 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
- 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/HT212978CVE reference · x_refsource_MISC
- https://support.apple.com/en-us/HT212979CVE reference · x_refsource_MISC
- https://support.apple.com/en-us/HT212981CVE reference · x_refsource_MISC
- https://support.apple.com/kb/HT213183CVE reference · x_refsource_CONFIRM
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.