Is CVE-2021-30663 actively exploited?

Yes. CVE-2021-30663 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, which means exploitation in the wild has been confirmed.

Can CVE-2021-30663 be exploited remotely?

The attack vector of CVE-2021-30663 has not been classified yet.

What is the CVSS score of CVE-2021-30663?

CVE-2021-30663 has not received a CVSS score yet.

HOME VULNERABILITIESCVE-2021-30663

HIGHCISA KEVIN THE WILD

CVE-2021-30663

Published: November 3, 2021

EPSS:1.11%probability of exploitation in 30 daysPercentile:77.8th

Official Description

Apple iOS, iPadOS, macOS, tvOS, and Safari WebKit contain an integer overflow vulnerability that leads to code execution when processing maliciously crafted web content. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple products which rely on WebKit for HTML processing.

NVD Source

CISA KEV Advisory

Apple Multiple Products WebKit Integer Overflow Vulnerability

Added to KEV: 2021-11-03Federal patch deadline: 2021-11-17

Required Action (CISA)

Apply updates per vendor instructions.

Risk Analysis

Apple iOS, iPadOS, macOS, tvOS, and Safari WebKit contain an integer overflow vulnerability that can lead to code execution when processing maliciously crafted web content. This high-severity flaw affects HTML parsers using WebKit, including Safari, and is confirmed to be actively exploited. The EPSS score of 0.01108 indicates a low but present likelihood of exploitation.

This vulnerability is actively being exploited in the wild and is listed in CISA's KEV catalog. Exploitation can occur remotely through maliciously crafted web content.

Recommended Action

Update iOS, iPadOS, macOS, tvOS, and Safari to the latest versions to patch the WebKit component. Exercise caution when browsing untrusted websites and opening suspicious web content.

Generated by the CTIWATCH analysis pipeline from this CVE's metadata (CVSS, EPSS, KEV status, exploit intelligence). Verify against vendor advisories before acting.

Technical Analysis

CVE-2021-30663 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

CISA has added CVE-2021-30663 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.