CVE-2025-43526
CRITICALCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
2Description
This issue was addressed with improved URL validation. This issue is fixed in Safari 26.2, macOS Tahoe 26.2. On a Mac with Lockdown Mode enabled, web content opened via a file URL may be able to use Web APIs that should be restricted.
Analysis
Apple Safari and macOS Lockdown Mode can be bypassed to access restricted Web APIs through maliciously crafted file URLs due to insufficient URL validation. Affects Safari 26.2 and macOS Tahoe 26.2 on systems with Lockdown Mode enabled. Remote attackers can potentially execute high-impact attacks leveraging APIs meant to be restricted in high-security configurations. EPSS score of 0.06% (18th percentile) indicates low observed exploitation probability. No public exploit identified at time of analysis. This represents a serious compromise of Apple's enhanced security feature designed to protect high-risk users from targeted attacks.
Technical Context
Apple's Lockdown Mode is an optional security feature introduced to protect users facing targeted digital threats by restricting certain Web APIs and advanced browser features. This vulnerability stems from inadequate URL validation (CWE-601: URL Redirection to Untrusted Site) in how Safari and macOS handle file:// protocol URLs when Lockdown Mode is active. The flaw allows file-based web content to bypass the restricted API enforcement mechanism, effectively neutralizing protections intended to limit attack surface against sophisticated adversaries. The affected products are Apple Safari browser (all versions prior to 26.2) and macOS operating system (versions prior to Tahoe 26.2). The vulnerability specifically undermines the trust boundary that should exist between local file content and web-origin-based security policies, allowing file URLs to access capabilities that Lockdown Mode explicitly aims to disable for threat mitigation.
Affected Products
This vulnerability affects Apple Safari browser versions prior to 26.2 and Apple macOS operating system versions prior to Tahoe 26.2 (macOS 26.2), specifically when Lockdown Mode is enabled on the system. The CPE identifiers are cpe:2.3:a:apple:safari:*:*:*:*:*:*:*:* for Safari and cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:* for macOS. Only Mac systems with the optional Lockdown Mode security feature activated are vulnerable to this API restriction bypass. Systems without Lockdown Mode enabled are not affected by this specific flaw. Official vendor advisories are available at https://support.apple.com/en-us/125886 for Safari and https://support.apple.com/en-us/125892 for macOS.
Remediation
Vendor-released patches are available and users should immediately update to Safari 26.2 and macOS Tahoe 26.2 (macOS 26.2), which address this issue through improved URL validation mechanisms. Organizations and individuals using Lockdown Mode should prioritize these updates as the feature's security guarantees are compromised in unpatched versions. Update Safari through the App Store or System Preferences Software Update mechanism, and update macOS through System Preferences/System Settings Software Update. Detailed installation guidance is provided in Apple's security advisories at https://support.apple.com/en-us/125886 (Safari) and https://support.apple.com/en-us/125892 (macOS). No effective workaround exists aside from disabling Lockdown Mode entirely, which would eliminate the intended security protections for high-risk users. Users should avoid opening untrusted file URLs or downloading files from unknown sources until systems are patched, particularly when Lockdown Mode is enabled.
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External POC / Exploit Code
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