{"id":"CVE-2020-9991","url":"https://www.cyber-defence.io/tools/cve/CVE-2020-9991","generatedAt":"2026-10-27T22:25:02.891Z","title":"A remote attacker may be able to cause a denial of service.","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.","published":"2020-12-08T22:15:19.000Z","lastModified":"2026-06-17T03:28:56.000Z","status":"Modified","sourceIdentifier":"product-security@apple.com","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":[],"affected":["apple/icloud","apple/ipados","apple/iphone os","apple/mac os x","apple/tvos","apple/watchos"],"epss":{"score":0.02822,"percentile":0.86484,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"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."},"changes":[],"references":[{"url":"http://seclists.org/fulldisclosure/2020/Dec/32","tags":["Mailing List","Third Party Advisory"],"source":"product-security@apple.com"},{"url":"https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E","source":"product-security@apple.com"},{"url":"https://support.apple.com/en-us/HT211843","tags":["Vendor Advisory"],"source":"product-security@apple.com"},{"url":"https://support.apple.com/en-us/HT211844","tags":["Vendor Advisory"],"source":"product-security@apple.com"},{"url":"https://support.apple.com/en-us/HT211847","tags":["Vendor Advisory"],"source":"product-security@apple.com"},{"url":"https://support.apple.com/en-us/HT211850","tags":["Vendor Advisory"],"source":"product-security@apple.com"},{"url":"https://support.apple.com/en-us/HT211931","tags":["Vendor Advisory"],"source":"product-security@apple.com"},{"url":"https://support.apple.com/kb/HT211846","tags":["Vendor Advisory"],"source":"product-security@apple.com"},{"url":"http://seclists.org/fulldisclosure/2020/Dec/32","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/en-us/HT211843","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/en-us/HT211844","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/en-us/HT211847","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/en-us/HT211850","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/en-us/HT211931","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/kb/HT211846","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2020-9991","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}