CVEs / CVE-2021-30666
CVE-2021-30666: Apple iOS WebKit Buffer Overflow Vulnerability
- Known exploited in the CISA KEV catalog since 3 Nov 2021
- high 8.8 CVSS 3.1 (NVD)
- EPSS 2.99% chance of exploitation in the next 30 days, higher than 87% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
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.
Description
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..
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Apple iOS | from unspecified, before 12.5 | 12.5 |
Exploitation
| In CISA KEV since | 3 Nov 2021 |
|---|---|
| Due date for US federal agencies | 17 Nov 2021 |
| Used in ransomware campaigns | Unknown |
| Required action | Apply updates per vendor instructions. |
Severity
| CVSS 3.1 | 8.8 highCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HScored by NVD |
|---|---|
| Weakness | CWE-119 |
References
- CVE-2021-30666 on NVD
- CVE-2021-30666 in the CISA KEV catalog
- CVE-2021-30666 on OSV
- https://support.apple.com/en-us/HT212341 Release Notes, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30666 Third Party Advisory, US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.