Apple Rolls Out Urgent Patches for Zero-Day Flaws Impacting iPhones, iPads and Macs

An out-of-bounds write issue was addressed with improved input validation. This issue is fixed in iOS 16.2 and iPadOS 16.2, macOS Ventura 13.1, tvOS 16.2, watchOS 9.2. An app may be able to execute arbitrary code with kernel privileges.

CVE-2023-32435 is an out-of-bounds write (CWE-787) memory corruption flaw in the WebKit engine shipped with Apple Safari, iOS, iPadOS, and macOS. It is triggered when WebKit processes maliciously crafted web content, such as a hostile webpage or embedded HTML, and successful exploitation leads to arbitrary code execution. Because WebKit is also used by non-Apple HTML parsers and applications, the impact extends beyond Safari and Apple's own browsers. CISA added the flaw to the Known Exploited Vulnerabilities catalog on 2023-06-23, confirming exploitation in the wild, though ransomware use is unknown and no public proof-of-concept is known. EPSS estimates a 22.8% probability of exploitation in the next 30 days (98th percentile), and a CVSS score is not yet published.

Do: Update Safari to 16.5 or later, iOS/iPadOS to 16.5 (or 15.7.6 on the legacy branch) or later, and macOS to the patched Ventura/Monterey/Big Sur releases (13.4 / 12.6.6 / 11.7.7) or later, then verify managed fleets are on fixed builds per the CISA KEV required action. Prioritize internet-exposed and high-risk users, since the flaw is confirmed exploited in the wild. If you ship or operate non-Apple products that embed WebKit, pull the fixed WebKit from the upstream project or your vendor.

CVE-2023-37450 is a high-severity (CVSS 8.8) arbitrary code execution vulnerability in Apple's WebKit browser engine, affecting iOS, iPadOS, Safari, macOS Ventura, tvOS, watchOS, and WebKitGTK. It is triggered when an affected device processes maliciously crafted web content — for example, when a user is lured into visiting an attacker-controlled webpage (user interaction is required, hence the UI:R CVSS vector). Successful exploitation grants the attacker arbitrary code execution within the web-content/browser context, the typical entry point for full iPhone, iPad, or Mac compromise chains. Anyone running iPhone OS/iPadOS earlier than 16.6, Safari earlier than 16.5.2, macOS Ventura earlier than 13.5, tvOS earlier than 16.6, watchOS earlier than 9.6, or unpatched WebKitGTK builds is affected. Apple reports the issue may have been actively exploited before it was patched, CISA added it to the KEV catalog on 2023-07-13, and EPSS assigns an 18.9% probability (97th percentile) of exploitation over the next 30 days.

Do: Upgrade immediately to iOS 16.6 / iPadOS 16.6, Safari 16.5.2, macOS Ventura 13.5, tvOS 16.6, and watchOS 9.6, or apply the latest available patch for older OS branches on devices that cannot take the 16.x/Ventura updates; this is a CISA KEV entry with a federal remediation requirement. Because exploitation occurs through normal web browsing, patching is the only reliable mitigation — avoid untrusted websites as an interim measure. WebKitGTK users should update to the latest patched WebKitGTK release and verify that dependent applications have been rebuilt against the fixed library.