CVE-2020-9991
A remote attacker may be able to cause a denial of service.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (2.82%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 2.82% probability · 86th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Affected
- apple/icloud · apple/ipados · apple/iphone os · apple/mac os x · apple/tvos · apple/watchos
- Source
- product-security@apple.com
EPSS 2.8% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://seclists.org/fulldisclosure/2020/Dec/32Mailing List, Third Party Advisory
- https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E
- https://support.apple.com/en-us/HT211843Vendor Advisory
- https://support.apple.com/en-us/HT211844Vendor Advisory
- https://support.apple.com/en-us/HT211847Vendor Advisory
- https://support.apple.com/en-us/HT211850Vendor Advisory
- https://support.apple.com/en-us/HT211931Vendor Advisory
- https://support.apple.com/kb/HT211846Vendor Advisory
- http://seclists.org/fulldisclosure/2020/Dec/32Mailing List, Third Party Advisory
- https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E
- https://support.apple.com/en-us/HT211843Vendor Advisory
- https://support.apple.com/en-us/HT211844Vendor Advisory
- https://support.apple.com/en-us/HT211847Vendor Advisory
- https://support.apple.com/en-us/HT211850Vendor Advisory
- https://support.apple.com/en-us/HT211931Vendor Advisory
- https://support.apple.com/kb/HT211846Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.