CVE-2021-30666

Apple iOS

Published 8 Sept 2021 · updated 17 Jun 2026 · Analyzed

8.8 High · CVSS 3.1, NVD

Exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on 3 Nov 2021, with a remediation deadline of 17 Nov 2021 for US federal agencies.

Required action: Apply updates per vendor instructions.

Description

A buffer overflow issue was addressed with improved memory handling. This issue is fixed in iOS 12.5.3. 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..

References

support.apple.com/en-us/HT212341 · Release Notes, Vendor Advisory
www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30666 · Third Party Advisory, US Government Resource