CVE-2020-9991
CVE-2020-9991 is a high-severity vulnerability in Apple Icloud with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- CVSS v2: 5.0
- EPSS exploit prediction: 3% (85th percentile)
- Actively exploited: Not listed in CISA KEV
- Affected product: Apple Icloud
- Published:
- Last modified:
Description
This issue was addressed with improved checks. This issue is fixed in macOS Big Sur 11.0.1, watchOS 7.0, iOS 14.0 and iPadOS 14.0, iCloud for Windows 7.21, tvOS 14.0. A remote attacker may be able to cause a denial of service.
Frequently asked questions
- What is CVE-2020-9991?
- This issue was addressed with improved checks. This issue is fixed in macOS Big Sur 11.0.1, watchOS 7.0, iOS 14.0 and iPadOS 14.0, iCloud for Windows 7.21, tvOS 14.0. A remote attacker may be able to cause a denial of service.
- How severe is CVE-2020-9991?
- CVE-2020-9991 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2020-9991 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-9991?
- CVE-2020-9991 primarily affects Apple Icloud. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2020-9991?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2020-9991 published?
- CVE-2020-9991 was published on 2020-12-08 and last updated on 2026-06-17.
References
- http://seclists.org/fulldisclosure/2020/Dec/32
- https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E
- https://support.apple.com/en-us/HT211843
- https://support.apple.com/en-us/HT211844
- https://support.apple.com/en-us/HT211847
- https://support.apple.com/en-us/HT211850
- https://support.apple.com/en-us/HT211931
- https://support.apple.com/kb/HT211846
Affected products (6)
- cpe:2.3:a:apple:icloud:*:*:*:*:*:windows:*:*
- cpe:2.3:o:apple:ipados:*:*:*:*:*:*:*:*
- cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
- cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
- cpe:2.3:o:apple:tvos:*:*:*:*:*:*:*:*
- cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:*
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