CVE-2025-46291: Apple macOS Gatekeeper Bypass Vulnerability

CVE-2025-46291 Overview

CVE-2025-46291 is a Gatekeeper bypass vulnerability in Apple macOS caused by a logic flaw in validation routines. An application running with local access can circumvent Gatekeeper security checks, allowing unsigned or unverified code to execute outside Apple's trust model. Apple addressed the issue with improved validation in macOS Tahoe 26.2.

The weakness maps to [CWE-693] (Protection Mechanism Failure) and affects the integrity, confidentiality, and availability of impacted systems. While no public exploit code is available and CISA has not added it to the Known Exploited Vulnerabilities catalog, Gatekeeper bypasses are routinely abused by macOS malware families to deliver second-stage payloads.

Critical Impact
A local application can bypass Gatekeeper checks, enabling execution of untrusted code without user notarization warnings and undermining a core macOS security boundary.

Affected Products

Apple macOS versions prior to macOS Tahoe 26.2
Applications relying on Gatekeeper for code signing and notarization enforcement
Endpoints where local code execution is achievable by an unprivileged user

Discovery Timeline

2025-12-17 - CVE-2025-46291 published to the National Vulnerability Database
2025-12-17 - Apple releases macOS Tahoe 26.2 with the security fix
2025-12-26 - Last updated in NVD database

Technical Details for CVE-2025-46291

Vulnerability Analysis

Gatekeeper is the macOS protection mechanism that verifies code signatures and notarization status before permitting execution of downloaded or quarantined applications. CVE-2025-46291 stems from a logic flaw in how Gatekeeper validates application metadata. An attacker-controlled application can present input that the validation routine processes incorrectly, allowing it to evade signature or notarization enforcement.

The vulnerability requires local execution context with low privileges and no user interaction. Successful exploitation grants the attacker the ability to run code that would otherwise be blocked by Gatekeeper, opening the door to persistence, lateral movement, or staged malware delivery. The flaw is categorized as a Protection Mechanism Failure, since it neutralizes an existing defense rather than introducing memory corruption.

Root Cause

Apple's advisory describes the root cause as a logic issue addressed with improved validation. Logic flaws in Gatekeeper historically involve mishandled extended attributes, malformed bundle structures, or alternate code paths that skip quarantine checks. The fix in macOS Tahoe 26.2 tightens the validation logic so that crafted applications can no longer bypass the trust evaluation.

Attack Vector

An attacker first achieves local code execution or convinces a user to run a crafted application. The malicious bundle is structured to exploit the validation logic flaw so that Gatekeeper approves execution despite the absence of valid Apple Developer ID signing or notarization. Once running, the payload operates with the privileges of the invoking user and can chain into further compromise. See the Apple Support Article for vendor details.

No verified proof-of-concept code is publicly available. The vulnerability manifests in Gatekeeper's policy evaluation path, and technical specifics have not been disclosed by Apple beyond the advisory text.

Detection Methods for CVE-2025-46291

Indicators of Compromise

Execution of applications lacking valid Developer ID signatures or notarization tickets that did not trigger Gatekeeper prompts
Unexpected processes spawned from ~/Downloads, /tmp, or other user-writable directories shortly after a download event
Removal or manipulation of the com.apple.quarantine extended attribute on recently introduced files
New LaunchAgents or LaunchDaemons registered by applications that were not gated by user approval dialogs

Detection Strategies

Audit spctl --assess --verbose results across endpoints to identify applications that should have been rejected by Gatekeeper
Correlate Unified Log entries from syspolicyd with process execution events to detect anomalous approvals
Monitor for processes invoking xattr -d com.apple.quarantine or programmatic equivalents that strip quarantine flags
Track macOS version inventory to prioritize endpoints running versions older than macOS Tahoe 26.2

Monitoring Recommendations

Enable endpoint telemetry that captures process creation, code signing status, and parent-child process relationships on macOS hosts
Forward syspolicyd and XProtect logs to a centralized analytics platform for retrospective hunting
Alert on first-seen unsigned binaries executing from user directories on patched and unpatched fleets

How to Mitigate CVE-2025-46291

Immediate Actions Required

Upgrade all eligible Mac systems to macOS Tahoe 26.2 or later as published in the Apple Support Article
Inventory macOS endpoints and prioritize patching for systems used by privileged users or developers
Restrict local user ability to download and execute applications from untrusted sources via MDM policies
Review recent application installations on unpatched endpoints for signs of Gatekeeper evasion

Patch Information

Apple resolved CVE-2025-46291 in macOS Tahoe 26.2 by introducing improved validation in the Gatekeeper code path. Administrators should deploy the update through Apple Software Update, MDM mechanisms such as Jamf or Intune, or Apple Business Manager. No backported fix is documented for earlier macOS major versions in the referenced advisory.

Workarounds

Enforce a managed allowlist of approved applications via MDM to limit execution of unknown binaries
Require notarization checks for all distributed software and block unsigned applications at the endpoint policy layer
Limit standard user accounts from installing software by removing local administrator rights where feasible
Use endpoint protection that inspects code signing posture independently of Gatekeeper's verdict

bash

# Verify current macOS version and Gatekeeper status
sw_vers -productVersion
spctl --status
spctl --assess --type execute --verbose /Applications/Example.app

# Trigger software update to install macOS Tahoe 26.2
sudo softwareupdate --install --all --restart