CVE-2016-4657
Apple iOS Webkit Memory Corruption Vulnerability
Apple iOS
WebKit in Apple iOS before 9.3.5 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 24 May 2022. US federal agencies were required to remediate it by 14 June 2022.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 66.8%, which is higher than 99.3% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Frequently asked questions
Is CVE-2016-4657 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2016-4657.
What does CVE-2016-4657 affect?
CVE-2016-4657 affects Apple iOS. WebKit in Apple iOS before 9.3.5 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site.
How severe is CVE-2016-4657?
CVE-2016-4657 is rated HIGH with a CVSS base score of 8.8. EPSS puts the probability of exploitation in the next 30 days at 66.8%, higher than 99.3% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 14 June 2022.
How should organisations respond to CVE-2016-4657?
Apply the vendor patch for Apple iOS as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.