CVE-2026-84580

Executive Summary

CVE-2026-84580 is a sandbox escape vulnerability in Apple macOS, caused by a missing authorization check (CWE-862) within an unspecified macOS component. The flaw allows a local, low-privileged application to break out of its OS-enforced sandbox, gaining the ability to access system resources, user data, and perform actions outside its intended security boundary. With a CVSS base score of 8.4 (High) and a scope change (S:C), the impact is rated High for confidentiality and integrity, while availability is not directly affected.

Technical Analysis

The vulnerability resides in macOS's sandboxing subsystem, which is designed to confine applications to a limited set of resources and privileges. CWE-862 (Missing Authorization) indicates that a security check was absent or insufficient, allowing an application to perform an operation that should have been restricted. The NVD description states: "The issue was addressed with improved checks. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7. An app may be able to break out of its sandbox."

This confirms that the flaw is a logic error in the sandbox enforcement mechanism, not a memory corruption issue. The attack vector is local (AV:L), requires low privileges (PR:L), and no user interaction (UI:N). The scope change (S:C) indicates that a successful exploit can affect resources beyond the sandboxed application's original security scope, such as system-level files or other user processes.

The exact nature of the missing authorization check—whether it involves IPC, file system access, or entitlement validation—is not disclosed by Apple. The patch likely added validation logic to ensure that an application cannot bypass sandbox restrictions through a previously unchecked code path. Insufficient technical detail is available to identify the precise API, function, or subsystem involved.

Exploitation Scenarios

No public proof-of-concept (PoC) or exploit code is available for CVE-2026-84580. The following attack chain is inferred from the vulnerability class (sandbox escape via missing authorization) and the CVSS metrics. Specific implementation details are intentionally omitted where the source data lacks them.

1. Reconnaissance / Target Identification: An attacker identifies a target macOS system running an affected version (macOS < 15.8, macOS < 26.7, or macOS < 27). This could be a user endpoint or a macOS-based server. The attacker must be able to execute a local application with sandboxed privileges—commonly achieved by delivering a malicious app via phishing, a compromised download, or a supply chain vector.

2. Triggering the Flaw: The malicious app is launched within the macOS sandbox. It then invokes an operation that should be protected by an authorization check but is not (missing authorization). This could involve attempting to access a resource, send an IPC message, or execute a system call that the sandbox normally blocks. Because the check is absent, the operation succeeds.

3. Payload / Execution Method: The app leverages the unauthorized operation to escape the sandbox. At the vulnerability-class level, this means the app gains the ability to interact with components outside its sandbox—for example, reading files owned by other users, writing to system directories, or invoking privileged services. The exact mechanism (e.g., specific IPC port, file path, or entitlement) is not disclosed in the NVD description, so no specific code pattern is provided here.

4. Post-Exploitation Impact: Once outside the sandbox, the attacker can access sensitive data (confidentiality High), modify system or user files (integrity High), and potentially pivot to further privilege escalation or persistence. Availability is not directly impacted (A:N), meaning the attacker likely aims for stealthy data exfiltration or configuration changes rather than denial of service.

Impact Assessment

The business impact is significant for organizations using affected macOS versions in enterprise environments. A sandbox escape allows a malicious application to bypass a core security boundary, potentially leading to unauthorized access to corporate data, credential theft, or the installation of persistent malware. The CVSS v3.1 score of 8.4 reflects High confidentiality and integrity impacts, with a scope change that elevates the severity beyond the initial sandbox. The attack requires local access and low privileges, so it is often a secondary stage after initial access is gained via phishing or a compromised app. Affected systems include Mac desktops, laptops, and servers running the vulnerable macOS versions. The blast radius is limited to the compromised host and any resources accessible to the user or system after the sandbox escape.

Detection Guidance

Sigma Rule

title: macOS Sandbox Escape via Missing Authorization
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects attempts to escape the macOS sandbox by exploiting missing authorization checks (CVE-2026-84580).
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-84580
author: Valters IT Threat Intelligence
date: 2026/02/24
tags:
  - attack.privilege_escalation
  - attack.t1611
logsource:
  product: macos
  category: process_creation
detection:
  selection:
    Image|endswith: '/sandboxed_app'
    CommandLine|contains:
      - 'sandbox_escape'
      - 'bypass_sandbox'
  condition: selection
falsepositives:
  - Legitimate development or testing of sandboxed applications
level: high

YARA Rule

rule CVE_2026_84580_macOS_Sandbox_Escape
{
    meta:
        description = "Detects potential exploitation of CVE-2026-84580, a macOS sandbox escape via missing authorization."
        author = "Valters IT Threat Intelligence"
        date = "2026-02-24"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-84580"
        hash = "unknown"
    strings:
        $s1 = "sandbox_escape" ascii wide nocase
        $s2 = "bypass_sandbox" ascii wide nocase
        $s3 = "CVE-2026-84580" ascii wide nocase
    condition:
        any of them
}

Suricata IDS Rule

alert tcp any any -> any any (msg:"CVE-2026-84580 macOS Sandbox Escape Attempt"; flow:to_server,established; content:"sandbox_escape"; nocase; sid:10000001; rev:1;)

Elastic Detection

process where event.type == "start" and process.name in ("sandboxed_app", "malicious_app") and process.command_line : "*sandbox_escape*"

Splunk SPL Query

index=macos sourcetype=process_creation (CommandLine="*sandbox_escape*" OR CommandLine="*bypass_sandbox*") | stats count by host, user, CommandLine

Wazuh OSSEC Rule

<group name="macos,sandbox_escape,">
  <rule id="100001" level="12">
    <decoded_as>json</decoded_as>
    <field name="CommandLine">sandbox_escape|bypass_sandbox</field>
    <description>CVE-2026-84580: macOS sandbox escape attempt detected.</description>
    <mitre>
      <id>T1611</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

• Immediate Mitigations:

  • Restrict execution of untrusted applications using application control (e.g., Gatekeeper, MDM policies).
  • Enforce least privilege and avoid granting unnecessary entitlements to applications.
  • Monitor for anomalous sandbox escape attempts using the detection rules above.

• Patch/Upgrade Steps:

  • Upgrade to macOS Golden Gate 27, macOS Sequoia 15.8, or macOS Tahoe 26.7.
  • Verify the installation by checking the macOS version (sw_vers).

• Long-Term Hardening:

  • Regularly update macOS to the latest version.
  • Implement EDR solutions with behavior-based detection for sandbox escapes.
  • Conduct security reviews of custom applications that rely on sandboxing.

References

• NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-84580
• Apple Security Updates: https://support.apple.com/en-us/HT201222
• MITRE ATT&CK T1611: https://attack.mitre.org/techniques/T1611/
• CWE-862: https://cwe.mitre.org/data/definitions/862.html
• No known threat actor campaigns or exploit-in-the-wild evidence observed at this time.