CVE-2026-43725: Safari Sandbox Escape Vulnerability – CVSS 7.1 HIGH

Technical summary

CVE-2026-43725 is a sandbox escape vulnerability stemming from insufficient input validation (CWE-20) in Safari and related Apple platforms. The vulnerability permits a malicious website to process restricted web content outside the sandbox boundary, effectively defeating the isolation mechanism that constrains web application privileges. The attack vector is network-based and requires user interaction (visiting a malicious site), but does not require authentication or special privileges. The fix involved implementing improved input validation across affected components.

Business impact

This vulnerability poses a significant risk to organizations and users relying on Safari for web browsing, particularly on macOS and iOS/iPadOS devices. A successful exploit could lead to unauthorized access to sensitive user data, credential theft, or lateral movement within a system. For enterprises managing Apple device fleets, this represents a HIGH-severity threat that could compromise data confidentiality, system integrity, and availability across multiple device categories (desktops, tablets, phones, wearables, and vision devices).

Affected systems

The vulnerability affects Safari 26.5.1 and earlier, iOS 26.5.1 and earlier, iPadOS 26.5.1 and earlier, macOS Tahoe versions prior to 26.5.2, tvOS 26.5 and earlier, visionOS 26.5 and earlier, and watchOS 26.5 and earlier. All platforms running the vulnerable Safari engine and WebKit implementations are at risk, making this a broad-based threat across Apple's ecosystem.

Exploitability

The vulnerability has a CVSS 3.1 score of 7.1 (HIGH) with a network attack vector and low attack complexity, indicating it can be exploited remotely without special setup. User interaction is required—the victim must visit a malicious website. The attack does not require prior authentication or elevated privileges. While no active exploitation has been reported in the CISA Known Exploited Vulnerabilities (KEV) catalog, the low barrier to exploitation and broad user base makes this a practical threat.

Remediation

Apply the patched versions immediately: Safari 26.5.2, iOS 26.5.2, iPadOS 26.5.2, macOS Tahoe 26.5.2, tvOS 26.6, visionOS 26.6, and watchOS 26.6. Verify patch availability through Apple's official security updates and deploy across all affected device classes.

Patch guidance

Deploy patches across your Apple device estate prioritizing user-facing devices (macOS, iOS, iPadOS) that are most likely to encounter untrusted web content. For tvOS, visionOS, and watchOS, patching may be lower priority depending on usage patterns but should still be completed. Verify patch installation through System Preferences > Software Update (macOS) and Settings > General > Software Update (iOS/iPadOS). For enterprises, coordinate deployment through MDM solutions to ensure comprehensive coverage.

Detection guidance

Monitor for unexpected process execution outside sandbox contexts and anomalous system calls from Safari or WebKit processes. Examine access logs for restricted system resources being queried from web browser processes. On macOS, review system.log and audit logs for sandbox policy violations. Implement network-level detection for malicious websites using threat intelligence feeds and DNS filtering. Consider behavioral analysis of Safari process execution patterns to identify exploitation attempts.

Why prioritize this

This HIGH-severity sandbox escape affecting multiple major Apple platforms warrants immediate patching due to the combination of remote exploitability, user-interaction requirement without authentication, and broad system impact (confidentiality, integrity, and availability). The cross-platform nature—affecting phones, tablets, desktops, and wearables—increases organizational risk. While not yet in the KEV catalog, the low attack complexity and widespread Safari usage make proactive patching critical to prevent exploitation.

Risk score, explained

The CVSS 3.1 score of 7.1 reflects a HIGH-severity vulnerability with network-based attack vector (AV:N), low attack complexity (AC:L), no privilege requirement (PR:N), and user interaction required (UI:R). The scope change (S:C) indicates the vulnerability can affect resources beyond the vulnerable component (sandbox boundary). Low confidence impact on confidentiality, integrity, and availability (C:L/I:L/A:L) accounts for the sandbox escape permitting unauthorized access to restricted resources without necessarily guaranteeing full system compromise. This score appropriately signals urgent remediation priority.

Frequently asked questions