CVE-2021-30858

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.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

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
• 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