How severe is CVE-2021-1799?

CVE-2021-1799 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2021-1799 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-1799?

CVE-2021-1799 primarily affects Apple Safari. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-1799?

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

When was CVE-2021-1799 published?

CVE-2021-1799 was published on 2021-04-02 and last updated on 2026-06-17.

CVE-2021-1799

CVE-2021-1799 is a medium-severity vulnerability in Apple Safari with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.3
EPSS exploit prediction: 2% (75th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Apple Safari
Published: 2021-04-02
Last modified: 2026-06-17

Description

A port redirection issue was addressed with additional port validation. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, tvOS 14.4, watchOS 7.3, iOS 14.4 and iPadOS 14.4, Safari 14.0.3. A malicious website may be able to access restricted ports on arbitrary servers.

Frequently asked questions

What is CVE-2021-1799?: A port redirection issue was addressed with additional port validation. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, tvOS 14.4, watchOS 7.3, iOS 14.4 and iPadOS 14.4, Safari 14.0.3. A malicious website may be able to access restricted ports on arbitrary servers.
How severe is CVE-2021-1799?: CVE-2021-1799 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2021-1799 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1799?: CVE-2021-1799 primarily affects Apple Safari. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-1799?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-1799 published?: CVE-2021-1799 was published on 2021-04-02 and last updated on 2026-06-17.

References

Affected products (9)

cpe:2.3:a:apple:safari:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:ipad_os:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:tvos:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:a:webkitgtk:webkitgtk:*:*:*:*:*:*:*:*

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