CVE-2021-30761
Apple iOS WebKit Memory Corruption Vulnerability
Apple iOS
A memory corruption issue was addressed with improved state management. This issue is fixed in iOS 12.5.4. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 3 November 2021. US federal agencies were required to remediate it by 17 November 2021.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 10.5%, which is higher than 95.8% 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-2021-30761 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2021-30761.
What does CVE-2021-30761 affect?
CVE-2021-30761 affects Apple iOS. A memory corruption issue was addressed with improved state management. This issue is fixed in iOS 12.5.4. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..
How severe is CVE-2021-30761?
CVE-2021-30761 is rated HIGH with a CVSS base score of 8.8. EPSS puts the probability of exploitation in the next 30 days at 10.5%, higher than 95.8% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 17 November 2021.
How should organisations respond to CVE-2021-30761?
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.