Critical 9.8Known exploited (CISA KEV)Published Apr 2, 2021

CVE-2021-1871A logic issue was addressed with improved restrictions.

Updated under an hour ago (Oct 27, 2026, 6:40 AM ET)

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It affects Apple iOS and iPadOS and 6 other products. Add what you run to find out whether that includes you.

CISA lists it as known exploited since Nov 3, 2021; federal agencies had to remediate by Nov 17, 2021. Treat that date as your deadline.

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Every CVE for Apple iOS and iPadOS

Exploited in the last 30 days

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..

CVSS: 9.8 CRITICAL (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Added to CISA KEV Nov 3, 2021; federal remediation due Nov 17, 2021Apply updates per vendor instructions.
EPSS (exploitation in the next 30 days): 7.00% (percentile 94)
Assigned by: apple
NVD analysis: Analyzed
Record last updated: Oct 21, 2025
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Apple iOS and iPadOS apple:ios_and_ipados (from the name)	from unspecified before 14.4	CNA record
Apple macOS apple:macos (from the name)	from unspecified before 11.2	CNA record
apple ipados apple:ipados	before 14.4	NVD
apple iphone_os apple:iphone_os	before 14.4	NVD
apple mac_os_x apple:mac_os_x	from 10.15 before 10.15.7; 10.15.7; 10.15.7; 10.15.7	NVD
apple macos apple:macos	from 11.0.1 before 11.2	NVD
debian debian_linux debian:debian_linux	10.0	NVD
fedoraproject fedora fedoraproject:fedora	33	NVD

References

References

https://support.apple.com/en-us/HT212147	x-refsource-misc, release-notes, vendor-advisory
https://support.apple.com/en-us/HT212146	x-refsource-misc, release-notes, vendor-advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/	vendor-advisory, x-refsource-fedora, broken-link, mailing-list
https://www.debian.org/security/2021/dsa-4923	vendor-advisory, x-refsource-debian, mailing-list, third-party-advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1871	us-government-resource

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.