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CVE-2021-30666: Apple iOS WebKit Buffer Overflow Vulnerability

criticalknown exploitedCVE-2021-30666
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
Apple iOS WebKit contains a buffer-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.

CSIRTS triage

vendor: Appleproduct: iOS WebKitRemote code execution
What
There is a buffer-overflow vulnerability that leads to code execution when processing maliciously crafted web content.
Who is affected
Deployments of Apple iOS WebKit, including Apple Safari and other products relying on WebKit.
Urgency
Remediation is urgent due to active exploitation and critical severity.
Action
Update to the latest version of iOS WebKit.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source
CISA Known Exploited Vulnerabilities (US · database · site)
Severity
critical
Published
2021-11-03
Exploitation
Observed in the wild (CISA KEV)

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2021-30666

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Referenced CVEs

CVECSIRTS overviewExternal
CVE-2021-30666coverage & exploitation statusNVD · CVE.org

Recent advisories for Apple iOS WebKit

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

More from CISA Known Exploited Vulnerabilities