How severe is CVE-2018-4377?

CVE-2018-4377 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2018-4377 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-4377?

CVE-2018-4377 primarily affects Apple Safari. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-4377?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-4377 published?

CVE-2018-4377 was published on 2019-04-03 and last updated on 2026-06-17.

CVE-2018-4377

CVE-2018-4377 is a medium-severity vulnerability in Apple Safari with a CVSS 3.x base score of 6.1. 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-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Apple Safari
Published: 2019-04-03
Last modified: 2026-06-17

Description

A cross-site scripting issue existed in Safari. This issue was addressed with improved URL validation. This issue affected versions prior to iOS 12.1, watchOS 5.1, Safari 12.0.1, iTunes 12.9.1, iCloud for Windows 7.8.

Frequently asked questions

What is CVE-2018-4377?: A cross-site scripting issue existed in Safari. This issue was addressed with improved URL validation. This issue affected versions prior to iOS 12.1, watchOS 5.1, Safari 12.0.1, iTunes 12.9.1, iCloud for Windows 7.8.
How severe is CVE-2018-4377?: CVE-2018-4377 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2018-4377 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-4377?: CVE-2018-4377 primarily affects Apple Safari. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-4377?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-4377 published?: CVE-2018-4377 was published on 2019-04-03 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:apple:safari:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:*
cpe:2.3:a:apple:icloud:*:*:*:*:*:*:*:*
cpe:2.3:a:apple:itunes:*:*:*:*:*:*:*:*

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