Security readout for executives and security teams
Plain-English summary
CVE-2021-30665 is an Apple memory corruption flaw triggered by malicious web content. Successful exploitation could let an attacker run code on an affected device. Apple reported possible active exploitation, and CISA lists it in the Known Exploited Vulnerabilities catalog, so exposed legacy Apple devices should be prioritized.
Executive priority
Treat this as urgent for legacy Apple fleets because exploitation is reported and the impact is code execution. The main business risk is compromise through malicious web content on unpatched devices, especially high-value users and unsupported assets.
Technical view
The issue is a CWE-787 out-of-bounds write class memory corruption vulnerability. The CVSS 3.1 score is 8.8, with network attack vector, low complexity, no privileges required, and user interaction required. Apple fixed it through improved state management across listed OS updates.
Likely exposure
Exposure is most likely on Apple devices running versions older than watchOS 7.4.1, iOS/iPadOS 14.5.1, iOS 12.5.3, tvOS 14.6, or macOS Big Sur 11.3.1. Evidence in the bundle does not define every affected build beyond Apple’s fixed-version advisories.
Exploitation context
Active exploitation is supported by Apple’s statement that it was aware of a report of exploitation and by CISA KEV inclusion. The source bundle does not provide exploit details, campaign scope, target sectors, or reliable public proof-of-concept status.
Researcher notes
The bundle identifies memory corruption with improved state management as the fix but does not include root cause detail, affected components, or exploit primitives. Validation should stay focused on patch-level evidence and Apple advisory mapping, not exploit reproduction.
Mitigation direction
- Update affected Apple devices to the fixed versions or later.
- Prioritize internet-browsing and executive-user Apple devices.
- Check Apple advisories for product-specific update availability.
- Remove or isolate unsupported devices that cannot receive fixes.
Validation and detection
- Inventory Apple OS versions across managed and unmanaged devices.
- Confirm devices meet or exceed the fixed versions listed by Apple.
- Review MDM compliance data for lagging iOS, macOS, tvOS, and watchOS assets.
- Track CISA KEV remediation status for regulated environments.
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-787: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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 lookupExecution 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-2021-30665 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
- 8.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://support.apple.com/en-us/HT212532CVE reference · x_refsource_MISC
- https://support.apple.com/en-us/HT212341CVE reference · x_refsource_MISC
- https://support.apple.com/en-us/HT212335CVE reference · x_refsource_MISC
- https://support.apple.com/en-us/HT212336CVE reference · x_refsource_MISC
- https://support.apple.com/en-us/HT212339CVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30665CVE 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.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.