CVE-2021-30858
HIGHCISA KEVEPSS 96th pctlDescription
A use after free issue was addressed with improved memory management. This issue is fixed in iOS 14.8 and iPadOS 14.8, macOS Big Sur 11.6. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploit Intelligence
Very high risk: more likely to be exploited than 96% of all known CVEs.
Apple iOS, iPadOS, macOS Use-After-Free Vulnerability
Apple iOS, iPadOS, and macOS WebKit contain a use-after-free vulnerability that leads to code execution when processing maliciously crafted web content. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple products which rely on WebKit for HTML processing.
Apply updates per vendor instructions.
Remediation due: 2021-11-17
References
- http://seclists.org/fulldisclosure/2021/Sep/25
- http://seclists.org/fulldisclosure/2021/Sep/27
- http://seclists.org/fulldisclosure/2021/Sep/29
- http://seclists.org/fulldisclosure/2021/Sep/38
- http://seclists.org/fulldisclosure/2021/Sep/39
- http://seclists.org/fulldisclosure/2021/Sep/50
- http://www.openwall.com/lists/oss-security/2021/09/20/1
- http://www.openwall.com/lists/oss-security/2021/10/26/9
- http://www.openwall.com/lists/oss-security/2021/10/27/1
- http://www.openwall.com/lists/oss-security/2021/10/27/2
- http://www.openwall.com/lists/oss-security/2021/10/27/4
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BO6DMTHZR57JDBOXPSNR2MKDMCRWV265/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XYNV7ASK4LQVAUMJXNXBS3Z7RVDQ2N3W/
- https://support.apple.com/en-us/HT212804
- https://support.apple.com/en-us/HT212807
- https://support.apple.com/kb/HT212824
- https://www.debian.org/security/2021/dsa-4975
- https://www.debian.org/security/2021/dsa-4976
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30858
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-10-27.