CVE-2025-31258: Apple macOS Privilege Escalation Flaw

CVE-2025-31258 Overview

CVE-2025-31258 is a sandbox escape vulnerability affecting Apple macOS. Apple addressed the issue by removing the vulnerable code in macOS Sequoia 15.5. An application running under the macOS sandbox can leverage the flaw to break out of its isolation boundary and access resources outside its intended scope.

The weakness is categorized under [CWE-284] (Improper Access Control). Apple published the fix in its security advisory for macOS Sequoia 15.5. Details were also shared publicly on the Full Disclosure mailing list.

Critical Impact
A malicious or compromised application can escape the macOS sandbox, gaining access to files, processes, or system resources that should be inaccessible from the confined context.

Affected Products

Apple macOS versions prior to macOS Sequoia 15.5
Applications relying on the macOS sandbox boundary for isolation
Third-party software shipped via the Mac App Store that depends on sandbox enforcement

Discovery Timeline

2025-05-12 - CVE-2025-31258 published to NVD
2025-05-12 - Apple releases macOS Sequoia 15.5 with the fix
2025-11-03 - Last updated in NVD database

Technical Details for CVE-2025-31258

Vulnerability Analysis

The macOS application sandbox restricts what a process can read, write, or execute by enforcing entitlements and Mandatory Access Control (MAC) policies. CVE-2025-31258 weakens that boundary. An app crafted to invoke the vulnerable code path can perform actions outside its allowed scope.

Apple's advisory states the issue was resolved by removing the vulnerable code entirely. This indicates the underlying functionality was either deprecated or unsafe by design rather than fixable through input validation. The vulnerability is classified as improper access control under [CWE-284].

Exploitation does not require user interaction in the affected component. The confidentiality and integrity of resources outside the sandbox are at risk, while availability is not affected according to the published CVSS vector.

Root Cause

The root cause is improper access control within a macOS component reachable from sandboxed processes. The component did not adequately validate the calling process's entitlements or boundary before performing privileged operations. As a result, a sandboxed app could request or trigger operations reserved for higher-privilege contexts.

Attack Vector

An attacker must first deliver or install a malicious application on the target system. Once executed within the sandbox, the application calls the vulnerable code path to escape isolation. Post-escape, the attacker can interact with files and system resources outside the sandbox container.

No public proof-of-concept is listed in the NVD references. Technical details were shared on the Full Disclosure mailing list. See the Full Disclosure Mailing List Post and the Apple Support Document for vendor information.

Detection Methods for CVE-2025-31258

Indicators of Compromise

Sandboxed applications writing to or reading from paths outside their container directory under ~/Library/Containers/<bundle-id>/
Unexpected child processes spawned by App Store or sandboxed applications
Unsigned or recently installed applications invoking private system frameworks shortly after launch

Detection Strategies

Monitor sandboxd and Endpoint Security framework events for sandbox violation reports tied to specific bundle identifiers
Baseline normal file and IPC access patterns for sandboxed apps, then alert on deviations
Correlate process execution telemetry with code signing identity to flag apps reaching resources outside their declared entitlements

Monitoring Recommendations

Ingest macOS Unified Logs for com.apple.sandbox subsystem entries and forward them to a central analytics platform
Track macOS build numbers across the fleet and alert on systems still running pre-15.5 releases
Review installed application inventories for unsigned or unnotarized binaries that could carry exploit code

How to Mitigate CVE-2025-31258

Immediate Actions Required

Update all eligible Mac systems to macOS Sequoia 15.5 or later as published in the Apple Support Document
Audit installed applications and remove software from untrusted sources
Enforce Gatekeeper and notarization requirements through MDM policy to block unsigned binaries

Patch Information

Apple addressed CVE-2025-31258 in macOS Sequoia 15.5 by removing the vulnerable code. Administrators should deploy this update through Software Update or their MDM solution. There is no separate standalone patch; the fix ships within the full 15.5 release.

Workarounds

Restrict installation privileges so only administrators can deploy new applications
Use MDM configuration profiles to allow execution only of signed, notarized applications from approved developers
Limit sandboxed apps' access to sensitive user data through Privacy Preferences Policy Control (PPPC) profiles until the update is applied

bash

# Verify the macOS version is patched (should report 15.5 or later)
sw_vers -productVersion

# Trigger an update check from the command line
sudo softwareupdate --list
sudo softwareupdate --install --all --restart