CVE-2021-30858
Apple iOS, iPadOS, and macOS WebKit contain a use-after-free 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.
A use after free issue was addressed with improved memory management. This issue is fixed in iOS 14.8 and iPadOS 14.8, macOS Big Sur 11.6. 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/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H- seclists.org/fulldisclosure/2021/Sep/25Mailing ListThird Party Advisory
- seclists.org/fulldisclosure/2021/Sep/27Mailing ListThird Party Advisory
- seclists.org/fulldisclosure/2021/Sep/29Mailing ListThird Party Advisory
- seclists.org/fulldisclosure/2021/Sep/38Mailing ListThird Party Advisory
- seclists.org/fulldisclosure/2021/Sep/39Mailing ListThird Party Advisory
- seclists.org/fulldisclosure/2021/Sep/50Mailing ListThird Party Advisory
- openwall.com/lists/oss-security/2021/09/20/1Mailing List
- openwall.com/lists/oss-security/2021/10/26/9Mailing List
- openwall.com/lists/oss-security/2021/10/27/1Mailing List
- openwall.com/lists/oss-security/2021/10/27/2Mailing List
- openwall.com/lists/oss-security/2021/10/27/4Mailing List
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BO6DMTHZR57JDBOXPSNR2MKDMCRWV265/Release Notes
Actively exploited. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1806 days
- CVSS
- 8.8 HIGH
- EPSS (30-day exploit probability)
- 13.4% · top 4% of all CVEs
- Weakness
- CWE-416
- Attack vector
- Network, remotely reachable
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.