CVE DATABASE / CVE-2021-30666
CVE-2021-30666
Apple iOS WebKit Buffer Overflow Vulnerability
CVSS 8.8 · HIGH
⚠ CISA KEV — ACTIVELY EXPLOITED
On the CISA KEV catalog
Confirmed exploited in the wild. Added 2021-11-03.
Federal remediation due 2021-11-17.
Required action: Apply updates per vendor instructions.
Summary
A buffer overflow issue was addressed with improved memory handling. This issue is fixed in iOS 12.5.3. 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..
CVSS 3.1 breakdown
| Base score | 8.8 (HIGH) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| Attack vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | REQUIRED |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity | HIGH |
| Availability | HIGH |
Weakness type (CWE)
Affected products
Apple iphone os
Check this CVE live
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References
- https://support.apple.com/en-us/HT212341
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30666
Data: NIST NVD + CISA KEV. NVD last modified 2025-10-23. Always verify against the vendor advisory before acting.