CVE-2021-1871
Apple iOS, iPadOS, and macOS WebKit Remote Code Execution Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 November 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
A logic issue was addressed with improved restrictions. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, iOS 14.4 and iPadOS 14.4. A remote attacker may be able to cause arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 7.00% probability · 94th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 3 November 2021 · due 17 November 2021
- Affected
- apple/ipados · apple/iphone os · apple/mac os x · apple/macos · debian/debian linux · fedoraproject/fedora
- Source
- product-security@apple.com
EPSS 7.0% since 30 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2021-1871
References
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/Broken Link, Mailing List
- https://support.apple.com/en-us/HT212146Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212147Release Notes, Vendor Advisory
- https://www.debian.org/security/2021/dsa-4923Mailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7E3RFYGLP7UFLXCG7TNLU/Broken Link, Mailing List
- https://support.apple.com/en-us/HT212146Release Notes, Vendor Advisory
- https://support.apple.com/en-us/HT212147Release Notes, Vendor Advisory
- https://www.debian.org/security/2021/dsa-4923Mailing List, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-1871US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.