CVE-2026-20666VulnerabilityPublished 11 Feb 2026Updated 2 Apr 2026

CVE-2026-20666: Apple macOS · An app may be able to access sensitive user data

Affects Apple macOSSource CVE Database V5

Not known to be exploited · CVSS 5.5 Medium : upgrade to 26.3 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

5.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 26.3

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Apple macOS to 26.3.

Affected software

Product	Affected	Fixed in
ApplemacOS	Affected <26.3	Fixed in 26.3

AI-suggested

To mitigate CVE-2026-20666, organizations should immediately apply the security update provided by Apple in macOS Tahoe 26.3 or later, as this patch addresses the underlying authorization state management flaw. Until patching is possible, restrict installation of untrusted or unnecessary applications on macOS devices to reduce the risk of local exploitation. Implement strict endpoint security controls including application whitelisting and least privilege policies to limit app capabilities. Monitor local system logs and user activity for unusual access patterns or attempts to access sensitive data by low-privilege applications. Employ data encryption and access controls at the file system or application level to add additional layers of protection for sensitive information. Educate users about the risks of installing unauthorized software and enforce policies to prevent privilege escalation. For environments with shared macOS systems, consider isolating user data and using separate user accounts with minimal privileges. Regularly review and audit macOS security configurations to ensure compliance with best practices. Finally, maintain an incident response plan to quickly address any suspected data exposure resulting from this vulnerability.

Description

An authorization issue was addressed with improved state management. This issue is fixed in macOS Tahoe 26.3. An app may be able to access sensitive user data.

Impact

The primary impact of CVE-2026-20666 is unauthorized disclosure of sensitive user data on affected macOS systems. Since the vulnerability allows an app with low privileges to bypass authorization controls, confidential information such as personal files, credentials, or other protected data could be exposed. Although the vulnerability does not affect system integrity or availability, the confidentiality breach can have serious consequences including privacy violations, intellectual property theft, and compliance failures. Organizations that rely on macOS devices for sensitive operations, especially those with multiple users or shared environments, face increased risk of insider threats or malware leveraging this flaw. The lack of required user interaction lowers the barrier for exploitation once local access is obtained, increasing the threat in environments where endpoint security is weak or where users may inadvertently install malicious software. However, the requirement for local access and low privileges means remote attackers cannot exploit this vulnerability directly, limiting its scope somewhat. Overall, the vulnerability poses a moderate risk to organizations worldwide, particularly those in sectors handling sensitive data such as finance, healthcare, government, and technology.

CWE-285Improper Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that you perform access control checks related to your business logic. These checks may be different than the access control checks that you apply to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
Attack patterns
Accessing Functionality Not Properly Constrained by ACLs (opens in a new tab)
Cross Zone Scripting (opens in a new tab)
Directory Indexing (opens in a new tab)
Subverting Environment Variable Values (opens in a new tab)
Using Malicious Files (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

support.apple.com/en-us/126348 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Apr 2026, 02:58 UTC

WeaknessesCWE-285

Technical details

References

Community reviews

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