How severe is CVE-2021-30818?

CVE-2021-30818 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-30818 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-30818?

CVE-2021-30818 primarily affects Apple Safari. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-30818?

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-2021-30818 published?

CVE-2021-30818 was published on 2021-10-28 and last updated on 2026-06-17.

CVE-2021-30818

CVE-2021-30818 is a high-severity vulnerability in Apple Safari with a CVSS 3.x base score of 8.8. 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-843.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.8
EPSS exploit prediction: 2% (72nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-843
Affected product: Apple Safari
Published: 2021-10-28
Last modified: 2026-06-17

Description

A type confusion issue was addressed with improved state handling. This issue is fixed in iOS 14.8 and iPadOS 14.8, tvOS 15, iOS 15 and iPadOS 15, Safari 15, watchOS 8. Processing maliciously crafted web content may lead to arbitrary code execution.

Frequently asked questions

What is CVE-2021-30818?: A type confusion issue was addressed with improved state handling. This issue is fixed in iOS 14.8 and iPadOS 14.8, tvOS 15, iOS 15 and iPadOS 15, Safari 15, watchOS 8. Processing maliciously crafted web content may lead to arbitrary code execution.
How severe is CVE-2021-30818?: CVE-2021-30818 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-30818 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-30818?: CVE-2021-30818 primarily affects Apple Safari. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-30818?: 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-2021-30818 published?: CVE-2021-30818 was published on 2021-10-28 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:a:apple:safari:*:*:*:*:*:*:*:*
cpe:2.3:o:apple:ipados:*:*:*:*:*:*:*:*
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:*:*:*:*:*:*:*:*

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Other CWE-843 vulnerabilities

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