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CVE Record

CVE-2021-1870: A logic issue was addressed with improved restrictions.

A logic issue was addressed with improved restrictions. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, iOS 14.4 and iPadOS 14.4. A remote attacker may be able to cause arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..

CriticalCVSS 9.8Known exploitedUpdated
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Glexia's TakeHuman reviewedcritical

Security readout for executives and security teams

Plain-English summary

CVE-2021-1870 is a critical Apple logic flaw that could let a remote attacker run code on affected devices. Apple fixed it in iOS 14.4, iPadOS 14.4, macOS Big Sur 11.2, and 2021-001 security updates for Catalina and Mojave. Apple reported possible active exploitation, and CISA lists it in KEV.

Executive priority

Treat this as urgent for any remaining legacy Apple fleet exposure. The issue is critical, remotely exploitable, and KEV-listed. Most organizations should prioritize proof of patch coverage over lengthy analysis because the fixes have been available since 2021.

Technical view

The source describes a logic issue corrected with improved restrictions. The impact is remote arbitrary code execution with CVSS 3.1 score 9.8. The provided affected products are Apple iOS/iPadOS and macOS, with fixed releases named but no detailed vulnerable version ranges or CWE mapping.

Likely exposure

Exposure is most likely on Apple iPhones, iPads, and Macs that missed the named January 2021 fixes. The source bundle does not provide exact vulnerable version ranges, so validate by installed OS version and vendor advisory mapping.

Exploitation context

Apple stated it was aware of a report that the issue may have been actively exploited. CISA KEV inclusion supports treating this as exploited in the wild. The sources do not provide exploit mechanics, campaigns, indicators, or affected victim profiles.

Researcher notes

The bundle gives strong impact and exploitation signals but limited root-cause detail. Avoid assuming affected subcomponents or vulnerable version ranges beyond the named Apple platforms and fixed releases. Fedora and Gentoo references indicate broader advisory tracking, but product impact should be verified from those advisories before scoping non-Apple assets.

Mitigation direction

  • Update iOS and iPadOS to 14.4 or later supported versions.
  • Update macOS Big Sur to 11.2 or later supported versions.
  • Apply Security Update 2021-001 on Catalina and Mojave systems.
  • Check Apple guidance for any newer replacement updates.
  • Prioritize unsupported devices for upgrade, isolation, or retirement.

Validation and detection

  • Inventory Apple devices and record exact OS versions.
  • Confirm iOS and iPadOS devices are at least 14.4.
  • Confirm macOS Big Sur devices are at least 11.2.
  • Confirm Catalina and Mojave have Security Update 2021-001 installed.
  • Review EDR or MDM telemetry for anomalous activity on previously unpatched devices.
Prepared
Reviewed
Confidence
high
Sources
8

Public sources used

Michael Williams reviewed this cited source version on .

Potential ATT&CK relevance

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.

description · low confidence lookup

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 lookup
cve · low confidence lookup

CVE-2021-1870 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.8 (3.1)
Known Exploited
Yes
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

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.

1CVSS vectors
0Timeline events
0ADP providers
7Source links

CISA KEV status

Status
Known exploited
Source
CISA / ADP
Date added
Not provided

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
9.8CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

9.8Critical
CVSS 3.1 vector shape for CVE-2021-1870Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
AppleiOS and iPadOSunspecifiedListed
ApplemacOSunspecifiedListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.