CVE-2021-1870VulnerabilityPublished 11/03/2021Updated 10/24/2026

CVE-2021-1870: Apple iOS, iPadOS, and macOS WebKit Remote Code Execution Vulnerability

Affects Apple iOS, iPadOS, and macOSSource CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 11/03/2021
KEV deadline: 11/17/2021
EPSS: 7.7% chance of exploitation in 30 days – higher than 94% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2021-1870 (opens in a new tab)

Description

CVE-2021-1870 is a high-severity remote code execution vulnerability in Apple iOS, iPadOS, and macOS WebKit. It involves an unspecified logic flaw that allows remote attackers to execute arbitrary code via crafted web content. This affects HTML parsers using WebKit, including Apple Safari and other products relying on WebKit for HTML processing. Exploits have been observed in the wild. No specific affected versions or patch information is provided in the available data.

Summary

This vulnerability (CVE-2021-1870) exists in the WebKit component of Apple iOS, iPadOS, and macOS. It is caused by an unspecified logic issue that enables remote attackers to execute arbitrary code by delivering crafted web content processed by WebKit's HTML parser. The flaw impacts not only Apple Safari but also other products that utilize WebKit for HTML processing. Exploitation in the wild has been confirmed, indicating active threat usage. No detailed technical specifics or patch information are included in the provided data.

Impact

Successful exploitation allows remote attackers to execute arbitrary code on affected devices running iOS, iPadOS, or macOS. This can lead to full compromise of the affected system. The vulnerability affects WebKit-based HTML parsers, broadening the potential attack surface beyond just Apple Safari. Known exploitation in the wild increases the urgency and risk associated with this vulnerability.

Mitigation

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no patch or official fix information is provided, users and administrators should monitor Apple security advisories for updates. Until a fix is available, limiting exposure to untrusted web content and disabling or restricting WebKit-based applications may reduce risk.

Weaknesses

CWE-1173Unclassified weakness (opens in a new tab)

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 09:41:12 UTC

Weaknesses

References

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