What happened

CISA added CVE-2021-30952 to the Known Exploited Vulnerabilities (KEV) catalog on 2026-03-05, signaling confirmed in-the-wild exploitation and setting a remediation due date of 2026-03-26 CISA KEV. The flaw is an integer overflow or wraparound (CWE-190) that, when triggered by processing maliciously crafted web content, may lead to arbitrary code execution NVD CVE-2021-30952. Affected “Apple Multiple Products” include Apple tvOS, macOS, Safari, iPadOS, and watchOS per the KEV entry scope CISA KEV. The vulnerability is tracked as CVE-2021-30952 and is recorded by MITRE and NVD with the same description and weakness mapping MITRE CVE.

Why it matters

Inclusion in KEV means federal agencies must patch because active exploitation has been observed, and the same urgency should carry to any organization relying on Apple platforms CISA KEV. The bug enables remote code execution (RCE) from untrusted web content, which compresses the attacker’s kill chain to a single web interaction such as a drive-by page load or a malicious link click NVD CVE-2021-30952. Because the scope spans multiple Apple operating systems and Safari, exposure often follows user browsing and embedded web views across the Apple ecosystem, widening the potential blast radius in mixed-fleet environments CISA KEV. The underlying weakness class is integer overflow/wraparound, a common source of memory corruption when arithmetic exceeds bounds and values wrap, enabling attacker-controlled state changes CWE-190.

Technical detail

CVE-2021-30952 is categorized under CWE-190 (Integer Overflow or Wraparound), where arithmetic on integer types exceeds their representable range and silently wraps, potentially corrupting memory or control data CWE-190. In this case, the vulnerable operation occurs while processing maliciously crafted web content, establishing a browser/web-content vector that can be triggered remotely NVD CVE-2021-30952. Successful exploitation may result in arbitrary code execution, implying that attacker-supplied payloads can run with the privileges of the affected process upon triggering the overflow condition MITRE CVE. The CISA KEV designation confirms that adversaries have leveraged this weakness in real attacks, elevating it from theoretical to operational risk CISA KEV.

The cross-product impact matters because many Apple workflows embed or invoke web rendering, including standalone Safari sessions and in-app web views, so a single exploitable condition in web content parsing can surface in multiple OS lines NVD CVE-2021-30952. The KEV catalog entry lists “Apple Multiple Products,” covering tvOS, macOS, Safari, iPadOS, and watchOS, reflecting this shared attack surface across platforms CISA KEV.

Defense

• Patch on deadline: CISA’s required action is to apply vendor mitigations or discontinue use if mitigations are unavailable, with a due date of 2026-03-26 for this KEV entry CISA KEV.
• Prioritize browser/web-content surfaces: Because the trigger is maliciously crafted web content, prioritize updating Safari and Apple OS components that handle web rendering across tvOS, macOS, iPadOS, and watchOS NVD CVE-2021-30952.
• Align with BOD 22-01 practices: Federal entities must follow KEV-directed remediation; enterprises should mirror the same urgency and governance for known exploited RCEs CISA KEV.
• Asset inventory and compliance tracking: Enumerate all endpoints and workloads running the affected Apple products and track patch state until closure under the KEV due date CISA KEV.

Known ransomware campaign use is listed as unknown in the KEV metadata; treat that as absence of evidence, not evidence of absence, and remediate on the basis of confirmed exploitation and RCE impact CISA KEV.

Lyrie Verdict

This is a web-content-triggered RCE across Apple platforms—exactly the kind of exploit path that compresses dwell time and benefits from automated delivery at machine speed NVD CVE-2021-30952. Lyrie’s stance: close the window with autonomous controls that gate access and quarantine unpatched surfaces the moment a KEV browser/renderer RCE is in play, and enforce policy by KEV due dates rather than human change-cadence CISA KEV. For this CVE, treat any process handling untrusted Apple web content as high-risk until verified patched, and drive automated patch-verification and isolation workflows tied to the KEV entry’s RCE semantics MITRE CVE.