Is CVE-2021-30666 actively exploited?

CVE-2021-30666 has no public evidence of in-the-wild exploitation as of 2025-10-23.

What is the CVSS score for CVE-2021-30666?

CVE-2021-30666 has a CVSS score of 8.8 (HIGH severity). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

How do I patch CVE-2021-30666?

Patch guidance is available from apple security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2021-30666.

Fix CVE-2021-30666 - HIGH apple iphone os

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..

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack Vector: network
Complexity: low
Privileges: none
User Action: required
Scope: unchanged
Confidentiality: high
Integrity: high
Availability: high
Weaknesses: CWE-119 · Memory Buffer Errors CWE-119 · Memory Buffer Errors

Metadata

Primary Vendor: APPLE
Published: 9/8/2021
Last Modified: 10/23/2025
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

CVE-2021-30666

Description

CVSS Metrics

Metadata

Affected Products

Remediation Guidance

Executive Summary