Security readout for executives and security teams
Plain-English summary
CVE-2016-4644 is an Apple credential-handling issue affecting older iOS, tvOS, and OS X El Capitan releases. Saved HTTP authentication credentials in Keychain could be affected by a downgrade issue. Apple says it fixed the issue by storing authentication types with credentials.
Executive priority
Prioritize this as a legacy-device hygiene issue rather than an emergency, unless affected systems remain in production with sensitive saved credentials. The absence of exploit evidence lowers urgency, but credential handling weaknesses can create business risk on unmanaged endpoints.
Technical view
The vulnerability concerns HTTP authentication credentials saved in Keychain on iOS before 9.3.3, tvOS before 9.2.2, and OS X El Capitan before 10.11.6 or Security Update 2016-004. The sources describe a downgrade issue, but provide no CVSS, CWE, attack prerequisites, or exploit mechanics.
Likely exposure
Exposure is most likely limited to legacy Apple endpoints or Apple TV devices still running the affected versions and using saved HTTP authentication credentials. Modern, updated Apple systems should not be considered exposed based on the provided sources.
Exploitation context
The provided sources do not state active exploitation, public exploit availability, or CISA KEV inclusion. Treat exploitation evidence as incomplete rather than confirmed. The issue is credential-related, so stale unmanaged devices deserve attention.
Researcher notes
Evidence is sparse: no CVSS, CWE, detailed affected CPEs, exploit status, or technical proof is included. The key source-grounded fact is Apple’s fix: storing authentication types with credentials to address a downgrade issue.
Mitigation direction
- Update iOS devices to 9.3.3 or later.
- Update tvOS devices to 9.2.2 or later.
- Update OS X El Capitan to 10.11.6 or Security Update 2016-004.
- Review Apple security guidance for any environment-specific instructions.
- Prioritize unmanaged or legacy devices that may retain saved HTTP credentials.
Validation and detection
- Inventory Apple devices and confirm operating system versions.
- Check MDM or asset records for affected iOS, tvOS, and OS X releases.
- Confirm applicable Apple security updates are installed.
- Review whether legacy systems store HTTP authentication credentials in Keychain.
- Document exceptions for devices that cannot be upgraded.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CVE-2016-4644 mapping review
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Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://support.apple.com/HT206902CVE reference · x_refsource_MISC
- https://support.apple.com/HT206903CVE reference · x_refsource_MISC
- https://support.apple.com/HT206905CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.