CVE-2021-30657: Apple macOS Unspecified Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 56 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 68.5%
EPSS score, percentile 99.3 of all scored records
- How severe?
- 5.5 Medium
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
CISA deadline . Apply updates per vendor instructions.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- before 11.3
- before 2021
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
Apply updates per vendor instructions.
CISA due date for this action: .
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | before 11.3 |
| Status | Versions |
|---|---|
| Affected | before 2021 |
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
Apple macOS contains an unspecified logic issue in System Preferences that may allow a malicious application to bypass Gatekeeper checks.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2021-30657 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Nov 2021.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 17 Nov 2021.
- The CVE record was published on 8 Sep 2021, 56 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 5.5 (Medium), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 68.5% (percentile 99.3), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact partial.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
A logic issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.3, Security Update 2021-002 Catalina. A malicious application may bypass Gatekeeper checks. Apple is aware of a report that this issue may have been actively exploited..
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
- CWE-862: Missing Authorization
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |
References
More exploited Apple vulnerabilities
- CVE-2026-86950: Apple Multiple Products Out-of-Bounds Write Vulnerability
- CVE-2026-65400: Apple macOS Improper Authentication Vulnerability
- CVE-2025-31277: Apple Multiple Products Buffer Overflow Vulnerability
- CVE-2025-43510: Apple Multiple Products Improper Locking Vulnerability
- CVE-2025-43520: Apple Multiple Products Classic Buffer Overflow Vulnerability
- CVE-2021-30952: Apple Multiple Products Integer Overflow or Wraparound Vulnerability