CVE-2021-30666: Apple iOS WebKit Buffer Overflow Vulnerability

Vulnerability summary

CVE-2021-30666 is a high (CVSS 8.8) vulnerability in Apple iOS. It is known to be exploited: CISA lists it, first on 03-11-2021. EPSS estimates a 3.00% chance of exploitation in the next 30 days, higher than 87.1% of scored vulnerabilities.

Timeline

1. 08-09-2021
   PublishedVulnerability first disclosed.
2. 03-11-2021
   Added to CISA KEVApple iOS WebKit Buffer Overflow Vulnerability
3. 17-11-2021
   CISA remediation dueApply updates per vendor instructions.
4. 21-10-2025
   Last modifiedVulnerability information updated.

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..

• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferThe product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.