Security readout for executives and security teams
Plain-English summary
CVE-2021-1871 is a critical Apple logic flaw where a remote attacker may cause arbitrary code execution. Apple fixed it in iOS/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 as urgent for any legacy or unmanaged Apple fleet because this is critical, remotely exploitable by description, and KEV-listed. Prioritize proof of patch coverage over theoretical analysis.
Technical view
The source describes a logic issue addressed with improved restrictions. The supplied CVSS is 9.8: network-accessible, low complexity, no privileges, no user interaction, with high confidentiality, integrity, and availability impact. The bundle does not identify the exact component, exploit chain, or detailed affected version ranges.
Likely exposure
Organizations may be exposed where Apple iOS, iPadOS, or macOS systems missed the named 2021 fixes. Fedora and Debian advisories also reference this CVE, so vulnerability managers should check those advisories only for assets using the relevant packaged software.
Exploitation context
Active exploitation is supported by Apple stating it was aware of a report of active exploitation and by CISA KEV inclusion. The provided sources do not include exploit details, observed targets, or confirmed exploitation scale.
Researcher notes
Evidence is strong for severity, vendor fixes, and exploitation signal, but sparse on root cause details. Avoid assuming a specific component or exploit method from this bundle alone. Track Apple, CISA KEV, Fedora, and Debian references for platform-specific applicability.
Mitigation direction
- Apply iOS and iPadOS 14.4 or later on affected devices.
- Apply macOS Big Sur 11.2 or later where applicable.
- Apply Security Update 2021-001 for Catalina or Mojave systems.
- Review Fedora and Debian advisories if those platforms are in scope.
- Check current vendor guidance for any later superseding updates.
Validation and detection
- Inventory Apple endpoints and record installed OS versions.
- Confirm iOS and iPadOS devices are at least 14.4.
- Confirm Big Sur systems are at least macOS 11.2.
- Confirm Catalina and Mojave systems have Security Update 2021-001.
- Check vulnerability scanners against CISA KEV and vendor advisory mappings.
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-2021-1871 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
- 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
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:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://support.apple.com/en-us/HT212147CVE reference · x_refsource_MISC
- https://support.apple.com/en-us/HT212146CVE reference · x_refsource_MISC
- FEDORA-2021-864dc37032CVE reference · vendor-advisory, x_refsource_FEDORA
- DSA-4923CVE reference · vendor-advisory, x_refsource_DEBIAN
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1871CVE 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.