CVE-2025-43443: 
Apple Safari vulnerability analysis and mitigation

CVE-2025-43443 is a WebKit vulnerability in Apple's web content processing engine that can cause an unexpected process crash when handling maliciously crafted web content. It was disclosed on November 3, 2025, and affects Safari (before 26.1), iOS and iPadOS (before 26.1 and before 18.7.2), macOS Tahoe (before 26.1), tvOS (before 26.1), visionOS (before 26.1), and watchOS (before 26.1). The vulnerability was reported by an anonymous researcher and is tracked via WebKit Bugzilla #299843. It carries a CVSS v3.1 base score of 4.3 (Medium), assigned by CISA-ADP (Apple iOS/iPadOS Advisory, Apple tvOS Advisory, Feedly).

The vulnerability resides in WebKit, Apple's browser engine, and was addressed with improved input validation checks (WebKit Bugzilla: 299843). Apple's advisory describes the root cause as a failure in internal checks during web content processing, classified broadly as insufficient information (NVD-CWE-noinfo). The Feedly executive summary characterizes it as a use-after-free or improper state management issue in web content processing, though Apple's official description specifically states it was fixed with "improved checks" rather than memory handling — distinguishing it from adjacent WebKit CVEs fixed in the same release that explicitly cite use-after-free or buffer overflow. Exploitation requires a user to visit or load maliciously crafted web content, making the attack vector network-based with required user interaction (Apple iOS/iPadOS Advisory, Apple tvOS Advisory, Apple visionOS Advisory).

Successful exploitation causes an unexpected process crash in the affected WebKit-based application (e.g., Safari or any app using WebKit for web rendering), resulting in a temporary denial of service for that application. There is no evidence of confidentiality or integrity impact — the CVSS score reflects availability impact only (Low). The scope is limited to the affected process and does not provide a pathway for code execution or lateral movement based on currently available information (Feedly, Apple iOS/iPadOS Advisory).

There is no public proof-of-concept exploit and no evidence of in-the-wild exploitation as of the time of this report. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.018% (0.000180), indicating a very low probability of exploitation in the near term. No threat actor attribution has been identified (Feedly).

Apple has released patches addressing this vulnerability across all affected platforms. Users should update to the following versions or later: Safari 26.1, iOS 18.7.2 / iPadOS 18.7.2, iOS 26.1 / iPadOS 26.1, macOS Tahoe 26.1, tvOS 26.1, visionOS 26.1, and watchOS 26.1. No configuration-based workaround is available; updating to a patched version is the only recommended remediation. Users should apply updates promptly via System Settings (macOS) or Settings > General > Software Update (iOS/iPadOS/watchOS/tvOS) (Apple iOS/iPadOS Advisory, Apple tvOS Advisory, Apple visionOS Advisory, Apple watchOS Advisory).

The vulnerability was covered as part of broader Apple security update coverage by technology media outlets including 9to5Mac, which reported on the iOS 26.1 and iPadOS 26.1 security fixes. The SANS Internet Storm Center also noted the release in its diary. IBM subsequently issued a security bulletin noting that IBM Observability with Instana (OnPrem) is also affected due to its use of WebKit components (IBM Advisory, SANS ISC). Community reaction has been routine, consistent with a medium-severity denial-of-service issue with no active exploitation.