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macOS CVE-2025-43526

CRITICAL
URL Redirection to Untrusted Site (Open Redirect) (CWE-601)
2025-12-17 product-security@apple.com
9.8
CVSS 3.1
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CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Analysis Generated
Apr 02, 2026 - 19:37 vuln.today
CVE Published
Dec 17, 2025 - 21:16 nvd
CRITICAL 9.8

DescriptionNVD

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.

AnalysisAI

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 ContextAI

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.

RemediationAI

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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CVE-2025-43526 vulnerability details – vuln.today

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