CVE-2021-30952: Apple Multiple Products High-Severity Vulnerability

What is CVE-2021-30952?

An integer overflow was addressed with improved input validation. This issue is fixed in tvOS 15.2, macOS Monterey 12.1, Safari 15.2, iOS 15.2 and iPadOS 15.2, watchOS 8.3. Processing maliciously crafted web content may lead to arbitrary code execution.

Technical Analysis

Weakness Classification

This vulnerability is classified as CWE-190 — Integer Overflow or Wraparound. An integer arithmetic operation produces a value that exceeds the maximum for its type, wrapping around and leading to unexpected behavior or buffer overflows.

Attack Vector Breakdown

• Attack Vector: Local
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required
• Scope: Unchanged
• Confidentiality: High
• Integrity: High
• Availability: High

Impact Analysis

Exploitation requires local access to the target system, such as a local user session or a malicious file opened by a user. The attack complexity is low, meaning exploitation does not depend on specialized conditions or race windows. Successful exploitation can result in full confidentiality breach (complete data disclosure), complete integrity compromise (data modification or code execution), total availability loss (denial of service). An integer arithmetic operation produces a value that exceeds the maximum for its type, wrapping around and leading to unexpected behavior or buffer overflows.

Exploitation Probability (EPSS): 0.79% chance of exploitation in the next 30 days (74th percentile). While the base probability may appear low, inclusion in CISA KEV confirms real-world exploitation is already occurring.

Is CVE-2021-30952 being exploited?

Yes. CVE-2021-30952 is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, restricted to CVEs with confirmed active exploitation in the wild. CISA added this vulnerability on 2026-03-05. Inclusion in KEV triggers the patching mandate under BOD 22-01 for U.S. federal civilian agencies, with a remediation deadline of 2026-03-26.

How to fix CVE-2021-30952

Update to the latest OS and software versions through System Settings > Software Update (macOS) or Settings > General > Software Update (iOS/iPadOS). For managed devices, deploy updates through MDM. Apple does not typically provide workarounds — updating is the primary remediation path. Check the Apple Security Releases page for the specific patch or update. CISA's Known Exploited Vulnerabilities catalog requires U.S. federal agencies to remediate this vulnerability by the due date shown below under Binding Operational Directive 22-01. Private organizations should treat KEV entries as priority-one patches because active exploitation has been confirmed in the wild.

Related Vulnerabilities

Other actively exploited vulnerabilities affecting Multiple Products or sharing the same weakness (CWE-190):

• CVE-2025-43510 (High 7.8) [same product] — A memory corruption issue was addressed with improved lock state checking…
• CVE-2025-43520 (Medium 5.5) [same product] — A memory corruption issue was addressed with improved memory handling. This…
• CVE-2025-31277 (High 8.8) [same product] — The issue was addressed with improved memory handling. This issue is fixed in…
• CVE-2023-43000 (High 8.8) [same product] — A use-after-free issue was addressed with improved memory management. This…
• CVE-2026-20700 (High 7.8) [same product] — A memory corruption issue was addressed with improved state management. This…

Frequently asked questions

Is CVE-2021-30952 critical?

CVE-2021-30952 has a CVSS 3.1 base score of 7.8 — High severity. It should be treated as a priority patch, especially given the active exploitation confirmed by CISA.

Is CVE-2021-30952 being actively exploited?

Yes — CISA added CVE-2021-30952 to the Known Exploited Vulnerabilities catalog on 2026-03-05. Inclusion in KEV means CISA has confirmed in-the-wild exploitation.

How do I patch CVE-2021-30952?

Apply the security update from Apple for Multiple Products. Federal agencies must remediate by 2026-03-26 under BOD 22-01. Refer to the Apple Security Releases for the official patch.

What type of vulnerability is CVE-2021-30952?

CVE-2021-30952 is classified under CWE-190 (Integer Overflow or Wraparound). An integer arithmetic operation produces a value that exceeds the maximum for its type, wrapping around and leading to unexpected behavior or buffer overflows.

What is the CVSS score for CVE-2021-30952?

CVE-2021-30952 has a CVSS 3.1 base score of 7.8, classifying it as High severity. The attack vector is Local, attack complexity is Low, and no privileges are required.