CVE-2021-1771
This issue was addressed with improved checks. This issue is fixed in macOS Big Sur 11.2,...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-1771- CVSS 3.1
- 3.3 Low
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2021-1771- Updated
- 2026-11-02
EUVDEUVD-2021-7235 No score
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.
- Record
EUVD-2021-7235- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-cv82-wvv8-3jrx No score
This issue was addressed with improved checks. This issue is fixed in macOS Big Sur 11.2,...
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.
- Record
GHSA-cv82-wvv8-3jrx- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-1771 is a low vulnerability (CVSS 3.3) in Apple Macos, published April 2, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.56%, the 47th percentile. No source names a fixed version.