What’s Vulnerable › Vulnerabilities

CVE-2016-4644

• Severity: medium (CVSS 6.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2019-01-11 · updated 2026-06-17
• Weakness: CWE-200

Description

In iOS before 9.3.3, tvOS before 9.2.2, and OS X El Capitan before v10.11.6 and Security Update 2016-004, a downgrade issue existed with HTTP authentication credentials saved in Keychain. This issue was addressed by storing the authentication types with the credentials.

Affected products

• Apple TV: before 9.2.2 — fixed in 9.2.2
• Apple Iphone Os: before 9.3.3 — fixed in 9.3.3
• Apple Mac Os: from 10.11.0 before 10.11.6 — fixed in 10.11.6

How to fix

Upgrade to a fixed version: Apple TV 9.2.2; Apple Iphone Os 9.3.3; Apple Mac Os 10.11.6. Check the vendor advisory for mitigations.

References

• https://support.apple.com/HT206902
• https://support.apple.com/HT206903
• https://support.apple.com/HT206905
• https://support.apple.com/HT206902
• https://support.apple.com/HT206903
• https://support.apple.com/HT206905

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