CVE-2021-1871

Name: CVE-2021-1871
Creator: NVD / NIST
Published: 2021-04-02T19:15:20.663+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10Actively ExploitedEPSS 7.12%

Last modified Jun 17, 2026

CVE-2021-1871 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. CISA has confirmed active exploitation in the wild. EPSS estimates a 7.12% chance of exploitation in the next 30 days.

Description

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..

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

7.12%

93.4th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Nov 17, 2021.

Affected Software

Vendor	Product	Versions
Apple	Ipados	< 14.4
Apple	Iphone Os	< 14.4
Apple	Mac Os X	>= 10.15, < 10.15.7
Apple	Mac Os X	10.15.7
Apple	Macos	>= 11.0.1, < 11.2
Debian	Debian Linux	10.0
Fedoraproject	Fedora	33

References

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/Broken Link, Mailing List
https://support.apple.com/en-us/HT212146Release Notes, Vendor Advisory
https://support.apple.com/en-us/HT212147Release Notes, Vendor Advisory
https://www.debian.org/security/2021/dsa-4923Mailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/Broken Link, Mailing List
https://support.apple.com/en-us/HT212146Release Notes, Vendor Advisory
https://support.apple.com/en-us/HT212147Release Notes, Vendor Advisory
https://www.debian.org/security/2021/dsa-4923Mailing List, Third Party Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1871US Government Resource

Timeline

Published: Apr 2, 2021
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-1871?

How severe is CVE-2021-1871?

CVE-2021-1871 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 7.12% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2021-1871?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-1871?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST