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Vulnerability record · CVE-2021-1771 · published 2 April 2021

CVE-2021-1771: Apple mac os x vulnerability

Apple · Mac Os X

This issue was addressed with improved checks. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave. A user that is removed from an iMessage group could rejoin the group.

3.3 CVSS 3.1 Low EPSS 0.55% · top 55.9%
3.3CVSS 3.1 base score, v2 4.3
0.55%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

This issue was addressed with improved checks. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave. A user that is removed from an iMessage group could rejoin the group.

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

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://support.apple.com/en-us/HT212147 Release NotesVendor Advisory
https://support.apple.com/en-us/HT212147 Release NotesVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-1771), CISA KEV, FIRST EPSS (scores of 2026-10-10). This page is refreshed as NVD updates the record.