Apple Mac OS X up to 10.11.5 Login Window access control

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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A vulnerability classified as critical was found in Apple Mac OS X up to 10.11.5 (Operating System). Affected by this vulnerability is some unknown processing of the component Login Window. The manipulation with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-264. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Login Window in Apple OS X before 10.11.6 allows attackers to gain privileges via a crafted app that leverages a "type confusion."

The weakness was disclosed 07/18/2016 by Stefan Esser with Zero Day Initiative as HT206903 as confirmed advisory (Website). It is possible to read the advisory at This vulnerability is known as CVE-2016-4638 since 05/11/2016. Attacking locally is a requirement. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK. The advisory points out:

A type confusion issue was addressed through improved memory handling.

The vulnerability scanner Nessus provides a plugin with the ID 92496 (Mac OS X 10.11.x < 10.11.6 Multiple Vulnerabilities), which helps to determine the existence of the flaw in a target environment. It is assigned to the family MacOS X Local Security Checks and running in the context c.

Upgrading to version 10.11.6 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (92496). The entries 88079, 89692, 89709 and 89685 are pretty similar.








  • end of life

CPE 2.3info

CPE 2.2info


VulDB CVSS-B Score: 🔍
VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
VulDB Reliability: 🔍


VulDB Meta Base Score: 7.8
VulDB Meta Temp Score: 7.6

VulDB Base Score: 7.8
VulDB Temp Score: 7.5
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍



VulDB Base Score: 🔍
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NVD Base Score: 🔍


Class: Access control
CWE: CWE-264
ATT&CK: T1068

Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍


Nessus ID: 92496
Nessus Name: Mac OS X 10.11.x < 10.11.6 Multiple Vulnerabilities
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 63631
OpenVAS Name: Apple Mac OS X Multiple Vulnerabilities December-2016
OpenVAS File: 🔍
OpenVAS Family: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍


Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Upgrade: Mac OS X 10.11.6


05/11/2016 🔍
07/18/2016 +68 days 🔍
07/18/2016 +0 days 🔍
07/18/2016 +0 days 🔍
07/19/2016 +1 days 🔍
07/21/2016 +2 days 🔍
07/21/2016 +0 days 🔍
09/06/2022 +2238 days 🔍



Advisory: HT206903
Researcher: Stefan Esser
Organization: Zero Day Initiative
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2016-4638 (🔍)
SecurityTracker: 1036348
SecurityFocus: 91824 - Apple Mac OS X APPLE-SA-2016-07-18-1 Multiple Security Vulnerabilities

scip Labs:
See also: 🔍


Created: 07/19/2016 07:36 PM
Updated: 09/06/2022 09:40 AM
Changes: 07/19/2016 07:36 PM (70), 03/03/2019 01:08 PM (13), 09/06/2022 09:40 AM (3)
Complete: 🔍


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