How severe is CVE-2016-4638?

CVE-2016-4638 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2016-4638 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-4638?

CVE-2016-4638 affects Apple Mac Os X. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-4638?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2016-4638 published?

CVE-2016-4638 was published on 2016-07-22 and last updated on 2026-06-17.

CVE-2016-4638

CVE-2016-4638 is a high-severity vulnerability in Apple Mac Os X with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-264.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 9.3
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-264
Affected product: Apple Mac Os X
Published: 2016-07-22
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2016-4638?: Login Window in Apple OS X before 10.11.6 allows attackers to gain privileges via a crafted app that leverages a "type confusion."
How severe is CVE-2016-4638?: CVE-2016-4638 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2016-4638 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-4638?: CVE-2016-4638 affects Apple Mac Os X. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-4638?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2016-4638 published?: CVE-2016-4638 was published on 2016-07-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*

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