Apple · iOS
CVE-2021-30666
Apple iOS WebKit Buffer Overflow Vulnerability
What it is
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..
CISA: 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.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: November 17, 2021
- Added to the CISA list
- November 3, 2021
- Published
- September 8, 2021
- Severity
- High 8.8 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 3.0% in the top 12.7% of all known vulnerabilities
- Weakness
- CWE-119
- More details
- NVD · CVE.org · CISA
All references (1)
More exploited flaws from Apple
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Dec 14, 2022 | Type Confusion | iOS | High 8.8 | 8.5% |
| May 24, 2022 | Information Disclosure | iOS | Medium 5.5 | 33% |
| May 24, 2022 | Memory Corruption | iOS | High 7.8 | 24% |
| May 24, 2022 | Webkit Memory Corruption | iOS | High 8.8 | 67% |
| May 23, 2022 | Memory Corruption | iOS | High 7.8 | 4.6% |
| Nov 3, 2021 | WebKit Memory Corruption | iOS | High 8.8 | 11% |
| Nov 3, 2021 | WebKit Use-After-Free | iOS | High 8.8 | 11% |
| Sep 29, 2026 | Out-of-Bounds Write | Multiple Products | High 8.8 | 26% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.